What Is a Tropical Cyclone?

October 25, 2026October 4, 2026 by admin

What Is a Tropical Cyclone?

Weather Guide • Extreme Weather • 7 minute read

A tropical cyclone seen from above: a calm eye, a ring of violent storms around it and spiral rain bands reaching far outward.

A tropical cyclone is a huge, rotating storm that forms over warm ocean water and can bring winds above 250 km/h, torrential rain and a wall of seawater onto the coast. Some are small and weak. The strongest are hundreds of kilometres wide and can affect millions of people. This guide explains what a tropical cyclone is, how it forms, what the different names mean and how to stay safe when one approaches.

The short answer: A tropical cyclone is a spinning storm system with a low-pressure centre, fed by heat and moisture from warm seas (about 26.5°C or more). Its winds spiral inward around a calm centre called the eye. It weakens quickly once it moves over cold water or land.

Tropical Cyclone, Hurricane and Typhoon: Same Storm, Different Names

These words describe the same type of storm. The name depends only on where it forms.

Name	Where it is used
Hurricane	North Atlantic Ocean, Caribbean Sea and the northeast Pacific
Typhoon	Northwest Pacific, including Japan, China and the Philippines
Cyclone	Arabian Sea, Bay of Bengal, South Pacific and Australian region

So a storm in the Arabian Sea that threatens Karachi or the Makran coast is called a cyclone, while the same kind of storm near Florida would be called a hurricane.

How Does a Tropical Cyclone Form?

A tropical cyclone needs several ingredients to come together at the same time. If one is missing, the storm usually fails to grow.

Warm ocean water: sea temperature of about 26.5°C or higher, reaching down roughly 50 metres. This is the fuel.
Moist air: humid air in the lower and middle atmosphere lets towering storm clouds keep growing.
Light upper-level winds: strong wind shear tears a young storm apart, so calm conditions are needed.
A starting disturbance: a cluster of thunderstorms or a low-pressure area to organise around.
Distance from the equator: the spin of the Earth (the Coriolis effect) is needed to make the storm rotate, so tropical cyclones almost never form within about 5 degrees of the equator.

Step by step

Warm sea water heats the air above it, and the moist air rises.
As the vapour rises and cools, it condenses into clouds and releases heat, which makes the air rise even faster.
Air at the surface rushes in to replace it, and the Earth’s rotation twists this inflow into a spiral.
The pressure at the centre keeps falling, the winds grow stronger and an eye can form.

Parts of a Tropical Cyclone

The eye

The eye is the centre of the storm, usually 30 to 65 kilometres wide. Skies can be clear and winds light. It can fool people into thinking the storm has ended, but the violent winds return from the opposite direction once the eye passes.

The eyewall

The eyewall is the ring of tall thunderstorms around the eye. It has the strongest winds and the heaviest rain in the entire cyclone.

Rain bands

Curved bands of showers and thunderstorms spiral outward from the centre. They can stretch far from the eye and bring gusts, heavy rain and even tornadoes long before the main part of the storm arrives.

Which Way Does It Spin?

In the Northern Hemisphere, a tropical cyclone rotates counter-clockwise. In the Southern Hemisphere, it rotates clockwise. Both are caused by the rotation of the Earth.

Stages and Strength of a Tropical Cyclone

A tropical cyclone grows through stages, based on its maximum sustained wind speed.

Stage	Sustained wind speed
Tropical depression	Below 63 km/h
Tropical storm	63 to 118 km/h
Category 1 hurricane or typhoon	119 to 153 km/h
Category 2	154 to 177 km/h
Category 3 (major)	178 to 208 km/h
Category 4 (major)	209 to 251 km/h
Category 5 (major)	252 km/h or more

These categories follow the Saffir-Simpson scale. Agencies in the North Indian Ocean use their own terms, such as cyclonic storm, severe cyclonic storm and very severe cyclonic storm, with slightly different wind thresholds. The category only measures wind. A weaker storm can still cause a disaster through rain or flooding.

Why Is a Tropical Cyclone So Dangerous?

Storm surge

The strong winds and the low pressure push the sea up and onto land as a wall of water. Storm surge is often the deadliest part of a tropical cyclone, especially along flat coastlines.

Destructive winds

Winds can tear off roofs, snap power poles, uproot trees and turn loose objects into flying debris.

Heavy rain and flooding

A slow-moving storm can drop huge amounts of rain. Flash floods and landslides can strike far inland, long after the winds have weakened.

Tornadoes

Rain bands can spawn short-lived tornadoes, mainly on the side of the storm where winds are strongest.

Where and When Do Tropical Cyclones Form?

Tropical cyclones form over warm tropical oceans. The main basins are the North Atlantic, the northeast and northwest Pacific, the North and South Indian Ocean and the Australian and South Pacific region. The Atlantic hurricane season officially runs from 1 June to 30 November. In the North Indian Ocean, activity peaks twice a year, before the monsoon (May and June) and after it (October and November).

Tropical Cyclones in Pakistan

Pakistan is not hit by cyclones as often as India or Bangladesh, but the risk is real. Storms form over the Arabian Sea and can threaten the coast of Sindh and Balochistan, including Karachi, Thatta, Gwadar and Ormara. Even when a cyclone does not make landfall, it can bring rough seas, strong winds, heavy rain, high tides and flooding. Cyclone Biparjoy in June 2023 is a recent example: it moved close to the Sindh coast, and thousands of people were moved to safer areas as a precaution. Fishermen are usually advised to stay out of the sea whenever a cyclone develops.

How Does a Tropical Cyclone End?

A tropical cyclone weakens when it loses its fuel. This happens when it moves over cold water, when it reaches land and loses the supply of warm moist air, or when strong wind shear breaks up its structure. A storm over land can still cause severe flooding for days, even after its winds have fallen.

Tropical Cyclone Safety Tips

Follow official warnings from your national weather service, such as the Pakistan Meteorological Department, and the instructions of local authorities.
Evacuate early if you are told to, especially if you live near the coast or in a low-lying area.
Prepare an emergency kit with drinking water, dry food, medicines, a torch, a power bank, a radio and copies of important documents.
Secure loose objects, shut windows and stay away from glass.
Do not go near the sea. Waves and surge can reach far beyond the beach.
Stay indoors, even if the eye passes over and it suddenly feels calm.
Never walk or drive through flood water.

For official forecasts and tracking maps, you can visit the National Hurricane Center. For updates in your area, check the live weather and weather maps on WeatherWorld.

Do Tropical Cyclones Get Names?

Yes. Naming storms makes warnings clearer and easier to remember, especially when more than one storm is active. Each region uses its own rotating lists of names agreed by the World Meteorological Organization. Names of especially deadly or costly storms are usually retired and never used again.

Is Climate Change Affecting Tropical Cyclones?

Research suggests that a warmer climate is making the strongest tropical cyclones more intense and increasing the amount of rain they produce. Rising sea levels also make storm surge more damaging. Scientists are less certain whether the total number of storms will change. This is an active area of study, and the details differ from one ocean basin to another.

Frequently Asked Questions

What is the difference between a tropical cyclone and a tornado?

A tropical cyclone is hundreds of kilometres wide, forms over the ocean and lasts for days. A tornado is only a few hundred metres wide, forms over land from a single thunderstorm and lasts for minutes.

Why is the eye of a tropical cyclone calm?

Air sinks in the centre of the storm, which warms and dries it and keeps clouds from forming. The strongest winds are in the eyewall just outside.

Can a tropical cyclone form on land?

No. It needs warm ocean water as fuel, so it dies out soon after moving inland.

How long does a tropical cyclone last?

Most last from several days to about two weeks, although some live longer if they stay over warm water.

Can we stop a tropical cyclone?

No. A strong one releases energy on a scale far beyond anything humans can control. The best defence is early warning, preparation and timely evacuation.

Final Thoughts

A tropical cyclone is one of the most powerful weather systems on Earth. It is born over warm seas, organised by the spin of the planet and carried toward land by the winds around it. Understanding how it forms and what it brings, from storm surge to flooding rain, helps you take warnings seriously and act early. Keep an eye on official forecasts during cyclone season, prepare before the storm approaches and never take a calm eye as a sign that the danger has passed.

Stay ahead of the storm: check the live weather, hourly forecast and weather maps on WeatherWorld.

What Is Atmospheric Pressure?

October 25, 2026October 4, 2026 by admin

What Is Atmospheric Pressure?

Weather Guide • Everyday Science • 6 minute read

Atmospheric pressure is the weight of the air above us, and it changes with height and weather.

You have never felt it as a weight, yet it is pressing on every centimetre of your body right now. Atmospheric pressure is so constant that we forget it exists, until we drive up a mountain and our ears pop, or until a weather forecaster says “falling pressure” just before a storm. This guide explains what it is, how it is measured and how a few simple readings can help you predict tomorrow’s weather.

The short answer: Atmospheric pressure is the force created by the weight of the air above a given spot. It is highest at sea level and falls as you climb. Changes in pressure over time are one of the most reliable early signs of a change in the weather.

Think of the Air as an Ocean

We live at the bottom of an ocean of air several hundred kilometres deep. Just as a diver feels more pressure at depth in the sea, we feel the combined weight of all the air stacked above us. Air seems weightless only because we are used to it. A large room contains many kilograms of it.

The reason we are not crushed is that the pressure inside our bodies pushes outward with the same force. The pressure is balanced from every side, so we never notice it.

How Pressure Is Measured

The most common unit in weather forecasts is the hectopascal (hPa), which is identical to the millibar. Average pressure at sea level is about 1013 hPa. Some countries use inches or millimetres of mercury, a unit that comes from the original barometer, which balanced a column of mercury against the weight of the air.

Mercury barometer: a tube of mercury whose height rises and falls with pressure.
Aneroid barometer: a sealed metal capsule that expands and contracts slightly. It is the type found in wall barometers and many instruments.
Electronic sensor: the tiny chip found inside most modern smartphones, watches and weather stations.

Why Pressure Falls as You Climb

The higher you go, the less air there is above you, so there is less weight pressing down. Pressure drops quickly at first. Around 5,500 metres up, it is about half of its sea-level value. This is why mountaineers struggle to breathe at great heights: the air contains the same share of oxygen, but each breath takes in fewer molecules.

Height above sea level	Approximate pressure	Example
0 m	1013 hPa	Karachi coast
500 m	955 hPa	Islamabad area
2,000 m	795 hPa	Murree and the Galiyat
3,500 m	655 hPa	High mountain passes
5,500 m	505 hPa	Base camps of high peaks

These numbers are rough averages. Real values vary a little with the weather of the day.

Signs of Pressure in Daily Life

Your ears popping

When you drive uphill or take off in a plane, the pressure outside drops faster than the pressure behind your eardrum. The extra air inside pushes outward until a small tube in your ear lets it escape with a pop. Swallowing or yawning helps open that tube.

Water boiling at different temperatures

Water boils when its vapour pressure matches the pressure around it. Where the air pressure is lower, such as in the mountains, water boils at a lower temperature, so rice and lentils can take much longer to cook. A pressure cooker does the opposite. It traps steam, raises the pressure and lets food cook faster at a higher temperature.

Sealed packets that swell

A packet of chips sealed at sea level looks puffed up when you carry it to the hills, because the air inside pushes against the lower pressure outside. It is a quick, visible reminder of the pressure change.

Drinking through a straw

When you suck on a straw, you reduce the pressure inside it. The higher air pressure outside then pushes the drink up into your mouth. Strictly speaking, the atmosphere does the pushing, not your lungs.

Highs and Lows on the Weather Map

Air pressure is not the same everywhere. Weather maps mark areas of higher pressure with an H and areas of lower pressure with an L.

High pressure: air slowly sinks and warms, which prevents clouds from forming. Skies are usually clear and winds are light. In winter, clear nights under a high can feel very cold, and in some regions they bring fog or smog.
Low pressure: air rises and cools, so moisture condenses into clouds. Expect cloud, wind and rain. The deeper the low, the stronger the weather.

Wind itself is air moving from high pressure toward low pressure. The bigger the difference over a short distance, the stronger the wind.

How to Read the Pressure Trend Yourself

A single number does not tell you much, but the direction and speed of change do. Most weather apps show pressure under the details of the forecast. Check it every few hours and compare.

What the pressure is doing	What it usually suggests
Rising slowly and steadily	Improving, settled weather
Rising quickly	Clearing skies, often with gusty wind
Steady	No big change soon
Falling slowly	Clouds increasing, a change within a day
Falling quickly	Storm, strong wind or heavy rain approaching

As a rough guide, a drop of around 3 hPa or more in three hours is worth paying attention to. Treat the trend as a clue and not as a guarantee, and always use it alongside the forecast. If a fast fall is accompanied by darkening skies, read our guide on how to prepare for a thunderstorm.

Why Weather Services Use “Sea-Level Pressure”

A reading taken in a hill town would always look lower than one taken at the coast, simply because of height. To compare places fairly, meteorologists convert each reading to what it would be at sea level. That adjusted value is what you see on most forecasts and maps. If your own barometer or phone sensor shows a lower number than the forecast, the difference is probably just your altitude.

Pressure and the Seasons in Pakistan

Pakistan’s weather follows large pressure patterns. In early summer, intense heat over the plains creates a broad area of low pressure that pulls in moist air from the sea, helping to start the monsoon. In winter, higher pressure over the region brings dry, cool, settled days, interrupted when western disturbances, which are moving areas of low pressure, bring rain and mountain snow. Watching the pressure trend during these transitions gives a useful early hint of what is coming.

Does Pressure Affect How You Feel?

Some people say that changes in pressure bring on headaches or joint pain. Scientific studies have not settled this question, and results are mixed. If you notice a pattern in yourself, keep a simple diary and talk with a doctor if it troubles you. At high altitude, however, the effect of low pressure on the body is well documented: breathlessness, tiredness and headaches are common until you adjust.

Frequently Asked Questions

What is a normal pressure reading?

Around 1013 hPa at sea level. In real life, values normally fall between roughly 980 and 1040 hPa.

Does low pressure always mean bad weather?

Often, but not always. It makes cloud and rain more likely, but the amount of moisture and other factors also matter.

Can my phone measure pressure?

Many phones contain a barometer sensor, and some apps display the reading. It is good for watching trends.

Why is the pressure different in the hills?

There is less air above you at higher places, so there is less weight pressing down.

Final Thoughts

Atmospheric pressure is the weight of the air around us, invisible but always working in the background. It explains why your ears pop on a mountain road, why food cooks differently at altitude and why weather maps are filled with highs and lows. Learn to watch the trend, rising for improvement and falling for change, and you gain one of the oldest and simplest forecasting tools there is.

See what the air is doing: check the live weather, hourly forecast and weather maps on WeatherWorld.

How Does a Rainbow Form?

October 25, 2026October 4, 2026 by admin

How Does a Rainbow Form?

Weather Science • Light and Sky • 6 minute read

A rainbow forms when sunlight passes through raindrops, with red on the outer edge and violet on the inner edge.

After a heavy shower, the clouds break, the sun slips out and a curved band of colour appears across the sky. People stop their cars, point their phones and fall silent for a moment. So how does a rainbow form? It is not a solid object or a painted arch. It is sunlight being bent, reflected and split into colours by millions of tiny raindrops. This guide explains the science in simple steps, why it forms an arc, and how you can find one yourself.

The short answer: A rainbow forms when sunlight enters raindrops, bends (refracts), reflects off the back of each drop and bends again as it leaves. Each colour bends by a slightly different amount, so white light is spread into red, orange, yellow, green, blue, indigo and violet.

What You Need to See a Rainbow

A rainbow needs three things at the same time:

Sunlight: the sun must be shining, and it must be low enough in the sky (below about 42 degrees above the horizon).
Water drops in the air: rain, drizzle, mist or the spray of a waterfall.
The right position: the sun must be behind you and the rain in front of you.

This is why rainbows usually appear when a shower is moving away and the sun is shining from the opposite side.

How Does a Rainbow Form? 5 Simple Steps

Sunlight enters a raindrop. Sunlight looks white, but it is a mixture of all colours.
The light bends (refraction). Light slows down when it passes from air into water, so its path bends as it enters the drop.
The colours separate (dispersion). Violet light bends the most and red light bends the least, so the colours start to spread apart inside the drop.
The light reflects. It hits the back of the drop and bounces toward the front.
The light bends again and leaves. As it exits, it bends once more, which spreads the colours even further, and they travel toward your eyes.

Each raindrop sends all the colours out in different directions. You only see one colour from each drop. Red comes from drops that are higher in the sky, and violet comes from drops that are lower. Millions of drops together build the full band of colour.

Why Is a Rainbow Shaped Like an Arc?

The light leaves the drops at a fixed angle: red light comes out at about 42 degrees from the line that runs from the sun through your head to the shadow of your head on the ground. All the drops that sit at the same angle from that line form a circle. The ground usually cuts off the lower half, so you normally see only an arc.

From an aeroplane, a mountain top or a hill, when the ground does not block the view, you can sometimes see a rainbow as a full circle.

The Colours of the Rainbow

Colour	Position in the rainbow	How much it bends
Red	Outer edge	Least
Orange	Next inward	Slightly more
Yellow	Middle upper	More
Green	Middle	More
Blue	Middle lower	More
Indigo	Inner	Even more
Violet	Inner edge	Most

The seven-colour list is a tradition. In reality, a rainbow is a smooth, continuous blend, and the colours fade into each other without sharp borders. Many people find it hard to pick out indigo.

What Is a Double Rainbow?

Sometimes a second, fainter rainbow appears above the main one. Here, the light has reflected twice inside each drop before coming out. A double bounce makes the colours flip, so the secondary rainbow has violet on the outside and red on the inside. It appears at about 51 degrees. The sky between the two bows often looks darker than the rest, and this dark band is known as Alexander’s band.

Where and When Can You See a Rainbow?

Early morning or late afternoon: the sun is low, so the rainbow rises high above the horizon. Around midday the sun is too high, and any rainbow would be below the horizon.
Just after a shower: when the sun comes out while raindrops are still falling.
Near waterfalls and fountains: the spray works like rain. A garden hose on a sunny day can make a small rainbow too.
In the monsoon season: in Pakistan, the monsoon months from July to September often produce showers that clear quickly with the sun still out, which makes them a good time to look for one. The hills of the north also give wide views of the sky after a storm.

Rainbow Myths and Facts

Does a rainbow have an end?

No. A rainbow is not in one fixed place. It depends on where you stand. Two people next to each other actually see slightly different rainbows, because each person receives light from different drops. If you walk toward it, it moves away, so you can never reach the end of it, or any pot of gold.

Is it a physical object?

No. It is an optical effect. You cannot touch it, and you cannot photograph it from “the side”.

Can you see rainbows at night?

Yes, but they are rare. A moonbow is made by moonlight on rain. It is usually very faint and looks whitish to the eye, because our eyes see colour poorly in the dark.

Other Rainbow-Like Sights

Fogbow: a pale, almost white arc seen in fog. The droplets are too small to separate the colours well.
Sundog: a bright coloured spot beside the sun, made by ice crystals in high clouds.
Halo: a ring around the sun or moon, also caused by ice crystals.

If you enjoy sky science, read about atmospheric pressure to see how pressure changes bring the showers that make rainbows possible.

Make Your Own Rainbow at Home

Choose a sunny day and stand with your back to the sun.
Use a garden hose with a spray nozzle, or a spray bottle, and make a fine mist in front of you.
Look at the mist. You should see a small rainbow, and it moves when you move.

Another way is to place a glass of water on a sunny windowsill, with a sheet of white paper on the floor. The water bends the light and may cast a small band of colour onto the paper.

Why Does the Sky Look Brighter Inside the Rainbow?

The area inside the primary bow is often brighter than the sky outside it. This is because the drops also scatter white light in that region, and the sum of all those light rays adds a soft glow. It is a small detail, but it shows how much is happening in a drop of water only a few millimetres wide.

Learn More

For further reading on how rainbows work, you can visit NOAA SciJinks. To check whether showers and sunshine are expected in your city, use the live weather and hourly forecast on WeatherWorld. Storms bring more dramatic skies too, so see our guide on what a tropical cyclone is.

Frequently Asked Questions

How does a rainbow form in simple words?

Sunlight enters raindrops, bends, bounces off the back and bends again as it leaves. This separates the white light into its colours.

Why is red on the outside of a rainbow?

Red light bends the least, so it leaves the drops at a larger angle. Violet bends the most, so it appears on the inside.

Why do we need the sun behind us?

The light comes back toward the same side it came from. The rainbow is always in the part of the sky opposite the sun.

Can a rainbow form without rain?

Yes. Any water drops in the air will work, such as mist, spray from a waterfall, a fountain or a garden sprinkler.

How long does a rainbow last?

Usually from a few minutes to about half an hour. It lasts as long as the sun and the falling drops stay in the right position.

Final Thoughts

A rainbow is a simple idea with beautiful results: sunlight, water and the right angle. Light bends as it enters each raindrop, bounces inside it and bends again on the way out, and every colour takes a slightly different path. The next time a shower ends while the sun is out, turn your back to the sun and look at the opposite sky. You may be rewarded with one of nature’s most graceful shows.

Plan your sky-watching: check the live weather, hourly forecast and weather maps on WeatherWorld.

How Does Snow Form?

October 25, 2026October 4, 2026 by admin

How Does Snow Form?

Weather Science • Winter Weather • 7 minute read

Snow forms when ice crystals grow inside a cold cloud, join into six-armed snowflakes and fall to the ground.

On a cold winter morning, the world can look completely different. Roofs, trees and mountains are covered in a soft white layer, and the air feels quiet. So how does snow form? It does not start as frozen rain. Snow is born high in a cloud, where tiny ice crystals grow, stick together and become heavy enough to fall. This guide explains how snow forms step by step, why every snowflake has six sides, and what decides whether you get snow, sleet or rain.

The short answer: Snow forms when water vapour in a cloud freezes onto a tiny particle and grows into an ice crystal. Many crystals join together into snowflakes, and if the air below stays cold enough, they fall as snow instead of melting into rain.

What Is Snow, Exactly?

Snow is a form of frozen precipitation made of ice crystals. A single ice crystal is not the same thing as a snowflake. A snowflake can be one crystal or a cluster of many crystals that have clumped together on their way down. Snow is white because the tiny surfaces of the crystals scatter all colours of light equally, so our eyes see white.

What Do You Need to Make Snow?

Snow needs a few things to be present together:

Moisture: water vapour in the air, usually in a thick cloud.
Cold air: temperatures at or below freezing (0°C) inside the cloud.
Something to freeze onto: a microscopic particle such as dust, pollen or a grain of salt. Scientists call it an ice nucleus.
Lift: air that is rising, for example along a mountain slope or at a weather front, so the cloud keeps growing.

How Does Snow Form? 6 Steps from Cloud to Snowflake

Air rises and cools. Moist air is pushed upward, and as it rises it cools until its water vapour condenses into cloud droplets.
Droplets stay liquid below freezing. Inside a cold cloud many droplets do not freeze right away, even at temperatures well below 0°C. These are called supercooled droplets.
Ice crystals appear. Some droplets freeze onto ice nuclei and turn into tiny ice crystals.
The crystals grow. Water vapour prefers to settle on ice rather than on liquid droplets, so the droplets slowly evaporate while the ice crystals grow bigger. Meteorologists call this the Bergeron process.
Crystals join together. As they move around, the crystals collide and stick, forming larger flakes.
The flakes fall. When they become too heavy for the rising air to hold, they fall. If the air near the ground is cold enough, they reach you as snow.

Why Do Snowflakes Have Six Sides?

The answer lies in the shape of a water molecule. When water freezes slowly from vapour, its molecules lock into a repeating pattern that has six-fold symmetry. This gives every ice crystal a six-sided base. As the crystal grows, the six corners stick out the furthest and catch the most vapour, so arms start to branch from them.

Is Every Snowflake Really Different?

Almost, yes. Each crystal follows its own path through the cloud, and the temperature and humidity change from place to place along the way. The arms of one crystal grow under nearly the same conditions, which is why they often look alike, but two crystals rarely follow the same journey. With so many possible paths, it is extremely unlikely that two complex flakes would match exactly. Simple shapes such as small plates can look very similar to each other.

Types of Snow Crystals

The shape of a crystal depends mostly on the temperature and the amount of moisture where it grows.

Crystal type	Approximate temperature	Look
Thin plates	Around 0 to -4°C and again near -15°C	Flat six-sided plates
Needles and columns	Around -4 to -10°C	Thin spikes or small hollow tubes
Branched stars (dendrites)	Around -12 to -18°C	Classic star shape with many branches

These ranges are approximate. The famous star-shaped snowflake seen in pictures forms only in a narrow band of cold, moist conditions, so most real snow is made of simpler or broken crystals.

Snow, Sleet, Freezing Rain and Hail: What Is the Difference?

Type	How it forms
Snow	Ice crystals fall through air that stays below freezing all the way down
Sleet	Snow melts in a warm layer, then refreezes into ice pellets in a cold layer near the ground
Freezing rain	Rain falls through a shallow cold layer and freezes when it touches the ground or objects
Hail	Ice balls grow in strong thunderstorms as updrafts carry them up and down through the cloud

Does It Have to Be Below Freezing for Snow to Fall?

Not at ground level. Snow can reach the surface when the air temperature is a degree or two above 0°C, especially if the air is dry, because melting takes time and evaporation cools the flakes. The important point is the whole column of air from the cloud to the ground. A warm layer anywhere in that column can turn snow into rain.

Why Is Snowy Weather So Quiet?

Fresh snow is full of air pockets, and these trap sound waves instead of reflecting them. A thick layer of new snow can reduce noise noticeably, which is why snowy days feel so calm. When snow gets packed down or turns icy, it reflects sound again.

How Much Water Is in Snow?

On average, about 10 centimetres of fresh snow melt down to roughly 1 centimetre of water. Light, fluffy snow in very cold air can hold much less water, while wet, heavy snow near freezing can hold much more. This is why wet snow is hard to shovel and can break branches and power lines.

Snow in Pakistan

Snow is a big part of winter in the north of Pakistan. It falls mainly on the mountains of Gilgit-Baltistan, Chitral, Swat, Kaghan and Naran, and in the Galiyat region around Murree. Higher parts of Balochistan, including Ziarat and Quetta, also see snow in some winters. Most of it arrives with western disturbances, which are moving areas of low pressure that carry moisture from the Mediterranean region and the Caspian Sea. Winter snow on the high peaks is very important, because it melts slowly in spring and summer and feeds rivers such as the Indus. Read about atmospheric pressure to see why falling pressure often comes before these storms.

Snow Safety Tips

Check the forecast and road reports before travelling to snowy areas such as Murree or the northern valleys.
Carry warm clothes, snow chains, a torch, water, dry snacks and a charged phone or power bank in your vehicle.
Drive slowly, keep a long gap and avoid sudden braking on snowy or icy roads.
Do not stay in a parked car with the engine running in deep snow without ventilation, because exhaust gas can build up and cause carbon monoxide poisoning.
Dress in layers and keep your hands, feet and head covered to avoid frostbite.
Stay away from steep slopes after heavy snowfall, because of the risk of avalanches.

Plan ahead with the live weather, hourly forecast and weather maps on WeatherWorld.

Learn More

If you enjoy sky science, look at how a rainbow forms or read about what a tropical cyclone is. For close-up pictures and research on snow crystals, visit SnowCrystals.com.

Frequently Asked Questions

How does snow form in simple words?

Water vapour freezes onto tiny particles in a cold cloud and grows into ice crystals. The crystals stick together into snowflakes and fall when they become heavy.

Is snow just frozen rain?

No. Frozen rain is sleet, which forms when raindrops freeze on the way down. Snow grows directly from vapour into ice crystals inside the cloud.

Why is snow white?

Snow is made of many tiny ice surfaces that scatter all colours of light. Together they look white.

What temperature does it need to be for snow?

The cloud needs to be below freezing, and the air near the ground is usually at or just above 0°C or colder. Very cold air makes small, dry flakes, while air near freezing makes large, wet flakes.

Why does it sometimes feel too cold to snow?

Very cold air holds little moisture, so there is less vapour to make crystals. Heavy snow is more common when the temperature is only a few degrees below freezing.

Final Thoughts

Snow begins as invisible vapour in a cold cloud and ends as a soft blanket on the ground. Each step matters: rising air, supercooled droplets, tiny particles to freeze onto, growing crystals and a cold path to the surface. The next time you watch snow falling, remember that every flake has taken its own journey through the sky, and that the snow on the mountains may be the water in a river months from now.

Ready for winter? Check the live weather, hourly forecast and weather maps on WeatherWorld.

What Is Air Quality and How Does Weather Affect It?

October 25, 2026October 4, 2026 by admin

What Is Air Quality and How Does Weather Affect It?

Weather Guide • Health and Environment • 7 minute read

Air quality changes with the weather: still air traps pollution near the ground, while wind and rain clear it away.

Some mornings the sky is crisp and blue, and the hills look close enough to touch. On other days a grey haze hangs over the city, your eyes sting and the sun looks like a pale disc. The difference is air quality, a measure of how clean or polluted the air around you is, and the weather is one of the biggest reasons it changes from day to day. This guide explains what air quality is, how the Air Quality Index works, which pollutants matter and exactly how wind, rain, heat and temperature layers change what you breathe.

The short answer: Air quality describes how much harmful gas and fine particles are in the air. Pollution comes from traffic, factories, burning and dust, but the weather decides whether it spreads out or builds up. Light wind, no rain and trapped cold air near the ground make air quality worse. Strong wind and steady rain make it better.

What Is Air Quality?

Air quality tells you how safe the air is to breathe. Clean air is mostly nitrogen and oxygen. When extra gases and tiny particles are added, such as smoke, dust, vehicle exhaust and chemical fumes, the air becomes polluted. Poor air quality affects everyone, but it is hardest on children, older people, pregnant women and anyone with asthma, heart disease or lung disease.

What Is the Air Quality Index (AQI)?

The Air Quality Index, or AQI, turns complicated pollution measurements into one simple number, usually from 0 to 500. The higher the number, the greater the health risk. Most apps and websites use colours that follow the scale below.

AQI	Category	What it means
0 to 50	Good	Air is clean and safe for everyone
51 to 100	Moderate	Acceptable, but a few very sensitive people may notice effects
101 to 150	Unhealthy for sensitive groups	Children, elderly and people with lung or heart problems should limit time outdoors
151 to 200	Unhealthy	Everyone may feel effects, and sensitive people may feel serious ones
201 to 300	Very unhealthy	Health warning: avoid outdoor exercise
301 and above	Hazardous	Emergency conditions: stay indoors

Different countries use slightly different scales and colours, so always check which one your app follows.

The Main Air Pollutants

PM2.5: very fine particles, thinner than a human hair. They reach deep into the lungs and even the bloodstream, and they are the main cause of haze and smog.
PM10: larger particles such as road dust, construction dust and pollen.
Ground-level ozone (O3): a gas formed when sunlight reacts with vehicle and industrial fumes. It is not emitted directly.
Nitrogen dioxide (NO2): comes mostly from vehicles and power plants.
Sulphur dioxide (SO2): comes from burning coal and oil.
Carbon monoxide (CO): an invisible gas from incomplete burning, such as in engines and stoves.

7 Ways Weather Affects Air Quality

The amount of pollution released is only half of the story. The weather decides where it goes.

1. Wind

Wind is the best natural cleaner. It carries pollution away and mixes it with fresh air. When the wind drops and the air becomes still, pollution stays over the city and the AQI climbs. Wind can also bring pollution from far away, so a clean city may suffer from smoke or dust that blew in from another region.

2. Rain

Rain washes particles out of the air and drops them on the ground. A good shower can clear a hazy sky within hours, which is why the air often smells fresh and looks sharper after rain. Very light drizzle helps less, and it can sometimes mix with pollution and make the air feel damp and heavy.

3. Temperature inversion

Normally, warm air near the ground rises and carries pollution upward. During a temperature inversion, a layer of warmer air sits above cooler air at the surface, like a lid. The pollution cannot rise, so it is trapped close to the ground. Inversions are common on cold, calm winter nights and mornings, especially in valleys and flat plains.

4. Sunlight and heat

Strong sunshine and high temperatures speed up the chemical reactions that make ground-level ozone. This is why ozone smog is worst on hot, sunny afternoons in summer. Heat can also increase fumes from fuel and paint.

5. Humidity and fog

Moist air lets tiny particles absorb water and grow, which reduces visibility. In winter, fog mixes with smoke and dust to make smog, a thick grey haze that can last for days.

6. High pressure and still air

A high-pressure system usually means calm winds and clear skies, but it also means sinking air that pushes pollution down and keeps it from spreading. Several days under a stagnant high can cause the worst air quality of the season. You can read more about this in our guide on atmospheric pressure.

7. Dust storms and smoke

Strong winds over dry land lift huge amounts of dust into the air and can move it hundreds of kilometres. Smoke from forest fires and from the burning of crop residue can do the same. In both cases, wind carries the pollution into places that did not produce it.

Air Quality in Pakistan

Air quality is a serious concern across much of Pakistan, especially in the cities of Punjab such as Lahore, Faisalabad and Multan. Heavy traffic, factories, brick kilns and the burning of crop waste add pollution all year. In late autumn and winter, cool air, low wind speeds and fog trap this pollution near the ground, and a thick smog covers the plains for weeks. Rain and strong winds from western disturbances often bring relief within a day or two. In spring and early summer, dust storms can push PM10 levels very high in a short time. Karachi has its own pattern: sea breezes usually help disperse pollution, but when the breeze is weak, the city’s traffic and industrial fumes build up.

How Poor Air Quality Affects Your Health

Irritated eyes, nose and throat, and coughing.
Asthma attacks and breathing difficulty.
Headaches and tiredness.
Over many years, a higher risk of heart disease, stroke and lung disease.

Short bursts of very bad air can be harmful, but long-term exposure to moderately polluted air also matters, because the effects add up.

How to Protect Yourself on Bad Air Days

Check the AQI each morning, using a trusted app or website, before planning outdoor activities.
When the AQI is high, avoid heavy exercise outside, and walk or exercise indoors instead.
Keep windows closed during peak smog hours. Open them when the air has cleared, usually in the afternoon.
Wear a well-fitting N95 or equivalent mask when you must go out. Ordinary cloth or surgical masks do not stop fine particles well.
Use an air purifier with a HEPA filter indoors if you can.
Drink plenty of water, and see a doctor if you have a persistent cough or breathing trouble.
Avoid burning rubbish, leaves or plastic. It adds to the problem for the whole neighbourhood.

Plan your day with the live weather, hourly forecast and weather maps on WeatherWorld.

How Can We Improve Air Quality?

Cleaner air depends on lowering the pollution that goes into the sky in the first place. Better public transport, cleaner fuel, well-maintained vehicles, modern brick kilns, proper waste disposal and tree planting all help. Weather can clear the air for a day, but it cannot fix a city that keeps adding pollution every day.

Learn More

For live air quality readings and health guidance, visit AirNow. To see how the sky changes after a shower, read how a rainbow forms, and for another extreme weather topic, see what a tropical cyclone is.

Frequently Asked Questions

What is air quality in simple words?

Air quality is a measure of how clean the air is. Good air quality means few pollutants. Poor air quality means the air contains harmful gases or tiny particles.

What is a good AQI number?

An AQI from 0 to 50 is considered good. Between 51 and 100 is moderate, and anything above 150 is unhealthy for everyone.

Does rain really clean the air?

Yes. Rain washes many particles out of the air. The effect is strongest with steady rain, and the air quality often improves quickly afterwards.

Why is air quality worse in winter?

Cold, calm nights create temperature inversions that trap pollution near the ground. Fog and smoke from heating and burning make it worse.

Can weather make air quality worse even if pollution stays the same?

Yes. With the same amount of pollution, calm air and an inversion can double or triple the concentration at ground level, while wind and rain can cut it sharply.

Is it safe to exercise outside when the AQI is high?

It is better not to. Heavy breathing pulls more pollution deep into your lungs. Exercise indoors until the AQI falls.

Final Thoughts

Air quality is something you cannot always see, but you can measure it, understand it and plan around it. Pollution sources set the baseline, and the weather decides whether the air is cleared or trapped. Make checking the AQI part of your daily routine, just like checking the temperature, and take extra care on calm, foggy, smoky or dusty days. Small steps, such as a mask, a closed window or an indoor workout, can protect your health when the air is at its worst.

Breathe easier: check the live weather, hourly forecast and weather maps on WeatherWorld.

Why Does Temperature Feel Different From the Actual Temperature?

October 25, 2026October 4, 2026 by admin

Why Does Temperature Feel Different From the Actual Temperature?

Weather Guide • Body and Weather • 7 minute read

The thermometer shows the air temperature, but humidity, wind and sunshine change how hot or cold it feels on your body.

Your phone says 35°C, yet you step outside and it feels like 45°C. Or the forecast shows 5°C and the wind makes it feel like freezing point. Why does temperature feel different from the number on the thermometer? The reason is that a thermometer measures only the temperature of the air, while your body responds to much more: moisture, wind, sunshine and even what you are wearing. This guide explains the science in simple steps, shows how the “feels like” temperature is worked out and tells you how to stay safe when the two numbers are far apart.

The short answer: The actual temperature is how warm the air is. The “feels like” temperature (also called the apparent temperature) is how warm or cold it seems to your body. Humidity makes hot weather feel hotter, wind makes cold weather feel colder, and strong sunshine adds extra heat on top of the air temperature.

Actual Temperature vs “Feels Like” Temperature

The actual temperature (air temperature) is measured by a thermometer kept in the shade, about 1.5 to 2 metres above the ground, so that sun and wind do not affect it. It is a clean, comparable number for every place.

The “feels like” temperature is a calculated value that tries to describe how the weather feels to a person. Weather services produce it by combining the air temperature with other factors such as humidity and wind speed. It is not a second thermometer reading. It is an estimate of how hard your body has to work to keep its balance.

How Your Body Decides What Feels Hot or Cold

Your body works to stay near 37°C inside. It constantly gains heat from food, movement and the sun, and loses heat to the surroundings. You feel comfortable when these are in balance. Your body cools itself in several ways:

Sweating: sweat takes heat from your skin as it evaporates. This is the main way you cool down in hot weather.
Convection: moving air carries heat away from your skin.
Radiation: your body gives off heat to cooler objects around you and gains heat from hotter ones such as the sun.
Conduction: heat passes directly to what you touch, such as a cold floor.

Whatever changes how fast these processes work changes what you feel. That is exactly what humidity, wind and sunshine do.

Why Does Temperature Feel Different? 6 Key Reasons

1. Humidity makes heat feel stronger

When the air is already full of water vapour, sweat cannot evaporate easily. It stays on your skin, and your body cannot cool down. The result is that the same temperature feels much hotter and stickier. Weather services call the calculated value the heat index.

Air temperature	Relative humidity	Approximate “feels like”
32°C	50%	About 35°C
32°C	70%	About 41°C
35°C	50%	About 42°C
35°C	70%	About 51°C

These figures are rounded from standard heat index charts. They are for shade and light wind, and direct sunshine can add more.

2. Wind makes cold feel colder

Your skin warms a thin layer of air around it. Wind blows that warm layer away and replaces it with colder air, so you lose heat faster. This is called wind chill. It affects people and animals, but it does not lower the temperature of objects like cars or water pipes. They only cool down to the air temperature.

Air temperature	Wind speed	Approximate “feels like”
10°C	30 km/h	About 7°C
5°C	30 km/h	About 0°C
0°C	30 km/h	About -6°C
-10°C	30 km/h	About -20°C

Wind chill is normally used only when the air is 10°C or colder and the wind is above about 5 km/h.

3. Sunshine adds heat

Standing in direct sun, your body absorbs the sun’s radiation in addition to the heat of the air. A day with clear sky and strong sunshine can feel several degrees hotter than the same air temperature under cloud. Dark clothes absorb more, and light clothes reflect more. This is why shade can feel so much cooler even when the thermometer barely changes.

4. Rain and wet clothes

Water draws heat away from your body far faster than air does. Wet clothes in cool, windy weather can make you feel colder than the temperature suggests, and can lead to a dangerous drop in body temperature. In hot weather, a light shower feels refreshing because evaporation cools your skin, although the relief fades when the humidity rises.

5. Surroundings and surfaces

Hot pavement, concrete walls and parked cars give off stored heat, which is why city streets stay warm long after sunset. This is part of the urban heat island effect. A grassy park or a street with trees can feel noticeably cooler than a paved road, even at the same air temperature.

6. Your own body and habits

People feel temperature differently. Age, fitness, body size, health and what you have eaten or drunk all play a part. People who live in a hot place are used to it (acclimatised) and sweat earlier and more efficiently. A person from a cooler region may struggle at the same temperature. Children, older adults and people with heart or lung conditions have a harder time adjusting to extremes.

How Is the “Feels Like” Temperature Calculated?

Different services use different names and formulas, and the number you see depends on the app.

Heat index: uses air temperature and humidity. Used in hot weather.
Wind chill: uses air temperature and wind speed. Used in cold weather.
Apparent temperature: a combined value that includes temperature, humidity and wind, and in some versions sunshine. Many weather apps and data services show this as “feels like”.
Wet-bulb globe temperature (WBGT): a more detailed index that includes humidity, wind, sun and heat radiation. It is used for sports and outdoor work safety.

Because the formulas differ, two apps can show slightly different “feels like” numbers for the same place. Use the number as a guide, and always think about your own situation, such as whether you are in sun or shade, walking or resting.

Why Does the Same Temperature Feel Different in Different Places?

A pleasant 25°C feels very different on a dry mountain slope, in a humid coastal city and in a closed room. Dry air allows sweat to evaporate quickly, so heat feels easier to bear. This is why 40°C in a dry desert feels different from 35°C in a humid port city. Altitude matters too: thinner air at height holds less heat, and the sun’s radiation is stronger, so you can feel sun-warmed and chilled in the shade at the same time.

Feels-Like Temperature in Pakistan

Pakistan offers good examples of this. In the plains of Punjab and Sindh, including cities like Multan, Lahore and Karachi, the early monsoon months of June to September can bring high humidity on top of high temperatures. A day with an air temperature of 38°C can feel like 45°C or more. Coastal Karachi often feels warmer than its thermometer reading because of the moist sea air, although the sea breeze helps in the afternoon. In the hills around Murree and in the northern valleys, winter wind can make a temperature just above freezing feel much colder, especially on exposed roads and ridges. Always look at the “feels like” value as well as the air temperature when you plan outdoor work, travel or sport.

Hot Weather Safety Tips

Drink water regularly, even before you feel thirsty.
Avoid hard work or exercise outside during the hottest hours, usually from late morning to late afternoon.
Wear loose, light-coloured cotton clothes and cover your head in the sun.
Rest in the shade or in a cool room, and never leave children or pets in a parked car.
Know the signs of heat exhaustion: heavy sweating, dizziness, headache, nausea and weakness. Move to a cool place and seek medical help if symptoms continue. Confusion or fainting is an emergency.

Cold Weather Safety Tips

Wear several thin layers, with a windproof outer layer, instead of one thick layer.
Cover your head, hands, feet and face, because these lose heat fastest.
Keep your clothes dry. Change out of wet clothes as soon as you can.
Watch for numb or pale fingers, toes, nose and ears, which are early signs of frostbite.
Shivering that will not stop, slurred speech or confusion can be signs of hypothermia, which needs urgent medical care.

Plan your day with the live weather, hourly forecast and weather maps on WeatherWorld.

Learn More

For official heat safety advice and the heat index chart, visit the National Weather Service heat safety page. To see how pressure and wind connect, read about atmospheric pressure. Weather also changes the air you breathe, so see what air quality is and how weather affects it, and for winter conditions read how snow forms.

Frequently Asked Questions

Why does temperature feel different from the actual temperature?

The thermometer only measures the air. Your body also reacts to humidity, wind, sunshine and what you are wearing, so what you feel can be higher or lower than the air temperature.

What is the “feels like” temperature?

It is a calculated value that estimates how warm or cold the weather seems to the human body. It combines air temperature with factors such as humidity and wind.

Why does humid heat feel worse than dry heat?

In humid air, sweat evaporates slowly, so your body cannot cool itself well. In dry air, sweat evaporates quickly and takes heat away.

Does wind chill lower the real temperature?

No. Wind chill only describes how fast your body loses heat. Objects such as cars and pipes do not drop below the actual air temperature because of wind.

Is the “feels like” temperature the same on every app?

No. Each service uses its own formula, so the numbers can differ by a degree or two. Treat them as a guide.

Which is more important, the actual or the feels-like temperature?

Both. The actual temperature is the weather fact. The feels-like temperature is more useful for deciding what to wear and how to stay safe outdoors.

Final Thoughts

The number on the thermometer is only part of the story. Humidity traps your sweat, wind carries your warmth away, sunshine adds heat and your own body decides the rest. The next time the “feels like” number is far from the real temperature, take it seriously: drink more water and rest in the shade when it is hot, and add layers and cover up when it is cold. A few minutes of planning can keep you comfortable, and safe, whatever the weather does.

Dress for the weather you feel: check the live weather, hourly forecast and weather maps on WeatherWorld.

What Is a Tornado and How Does It Form?

October 25, 2026October 4, 2026 by admin

What Is a Tornado and How Does It Form?

Weather Guide • Severe Weather • 7 minute read

A tornado is a violently rotating column of air that reaches from a thunderstorm cloud down to the ground.

In a few minutes, a calm afternoon can turn dark, the wind can drop suddenly and a grey funnel can drop out of the sky. So what is a tornado, and how does it form? A tornado is a violently rotating column of air that stretches from a thunderstorm cloud to the ground. It is small compared to a tropical cyclone, but at close range it can be the most violent wind on Earth. This guide explains what a tornado is, how it forms step by step, how tornadoes are rated and how to stay safe.

The short answer: A tornado forms when a thunderstorm contains a rotating updraft, usually in warm, moist and unstable air with winds that change speed and direction with height. The spinning column tightens, stretches down from the cloud and touches the ground. Most tornadoes last only a few minutes, but the strongest can destroy well-built houses.

What Is a Tornado?

A tornado is a narrow, violently rotating column of air that is in contact with both the ground and a cloud above it. The visible part is the funnel, which is made of water droplets that condense as pressure drops inside the vortex. Dust and debris near the ground often make the base look dark. If the funnel is in the air and has not reached the ground, it is called a funnel cloud, and it only counts as a tornado once it touches down.

Width: usually 50 to 200 metres, although the biggest can be more than 2 kilometres wide.
Life span: mostly a few minutes, though a rare long-track tornado can last over an hour.
Wind speed: from about 105 km/h in the weakest to over 400 km/h in the most violent.
Direction of spin: counter-clockwise in most tornadoes in the Northern Hemisphere, but a few spin the other way.

What Do You Need to Make a Tornado?

Tornadoes are born inside severe thunderstorms. Several ingredients must meet in the same place:

Warm, moist air near the ground: this is the fuel, and it often flows in from a warm sea or a humid region.
Cooler, drier air above: it makes the atmosphere unstable, so warm air rises strongly once it is lifted.
A lifting trigger: a cold front, a dry line, a sea breeze or a mountain slope pushes the air up.
Wind shear: the wind changes speed and direction with height, for example a light south wind at the surface and a strong west wind higher up. This is the source of the spin.

How Does a Tornado Form? 6 Steps

The air becomes unstable. Warm, moist air sits under a layer of cooler, drier air, like a pot ready to boil.
A storm starts to grow. Something lifts the warm air, and it rises quickly, forming a tall thunderstorm cloud.
Wind shear makes a rolling tube. The faster wind above and the slower wind below create a horizontal spinning tube of air, a little like a rolling pin turning in the sky.
The updraft tilts the tube upright. The storm’s strong updraft lifts the middle of the tube and tilts it into a vertical column. The storm itself now rotates. This rotating updraft is called a mesocyclone, and the storm is a supercell.
The rotation tightens. As a cool downdraft wraps around the rotation and the updraft stretches the column upward, the spin gets narrower and faster, just as a skater spins faster by pulling in their arms.
The funnel touches down. The low-pressure core extends from the cloud base to the ground. Once it reaches the surface, it is a tornado.

Not every supercell makes a tornado, and scientists are still studying why some do and others do not. Many tornadoes also form from other kinds of storms, such as lines of thunderstorms and the outer rain bands of a tropical cyclone, but these tend to be weaker and shorter.

Warning Signs of a Tornado

A dark, sometimes greenish sky.
Large hail, especially with little or no rain.
A rotating, lowering cloud base or a wall cloud.
A sudden calm after heavy rain or hail.
A loud, continuous roar, often compared to a freight train.
Dust or debris swirling near the ground, even when no funnel is visible.

How Strong Is a Tornado? The Enhanced Fujita (EF) Scale

Tornadoes are rated by the damage they cause, since it is rarely possible to measure the wind directly. The Enhanced Fujita scale runs from EF0 to EF5.

Rating	Estimated wind speed	Typical damage
EF0	105 to 137 km/h	Light: branches broken, some roof tiles lifted
EF1	138 to 177 km/h	Moderate: roof surfaces peeled, mobile homes pushed over
EF2	179 to 218 km/h	Considerable: roofs torn off, large trees snapped
EF3	219 to 266 km/h	Severe: walls knocked down, trains overturned
EF4	267 to 322 km/h	Devastating: well-built houses levelled
EF5	Over 322 km/h	Incredible: strong buildings swept off their foundations

Most tornadoes are weak (EF0 or EF1). Only a small share reach EF4 or EF5, but these cause most of the deaths.

Where Do Tornadoes Happen?

Tornadoes occur on every continent except Antarctica. The United States has the most, especially across the central plains often called Tornado Alley, where warm, moist air from the Gulf of Mexico meets cold, dry air from Canada and dry air from the Rocky Mountains. Other regions include Argentina and Uruguay, Bangladesh and eastern India, and parts of Europe, Australia and South Africa. Bangladesh has suffered some of the deadliest tornadoes in history, because of its dense population and the strong storms of the pre-monsoon season.

Tornadoes in Pakistan

Pakistan does not have a regular tornado season like the central United States, and strong tornadoes are rare. Still, severe thunderstorms in the pre-monsoon and monsoon months, especially across Punjab and the upper Sindh plains, can produce short-lived tornadoes, as well as damaging downburst winds and dust storms. Damage from a sudden windstorm is often mistaken for a tornado, which is why a trained survey of the damage pattern is needed to tell them apart. Always follow warnings from the Pakistan Meteorological Department when a severe storm is forecast.

Tornado vs Hurricane vs Dust Devil vs Waterspout

Phenomenon	Size and life span	Key difference
Tornado	Tens to hundreds of metres, minutes	Born from a thunderstorm, with extreme local winds
Tropical cyclone	Hundreds of kilometres, days	Forms over warm seas, brings surge and flooding rain
Dust devil	A few metres, minutes	Forms on hot, clear days from rising hot air, not from a storm, and is much weaker
Waterspout	Tens of metres, minutes	A spinning column over water. Some are tornadoes over water, while most “fair-weather” types are weak

To compare with a much larger spinning storm, read what a tropical cyclone is.

Tornado Safety Tips

Know the difference between a watch (conditions are right for a tornado) and a warning (a tornado is happening or about to happen). Act at once on a warning.
Go to the lowest floor of a strong building, such as a basement or a small interior room away from windows. Put as many walls as you can between you and the outside.
Cover your head and neck with your arms, a mattress, heavy blankets or a helmet.
Do not stay in a mobile home or a light, temporary shelter. Move to a stronger building if there is time.
Do not try to outrun a tornado in a car in heavy traffic. If you are caught outdoors with no shelter, lie flat in a low area and cover your head. Avoid highway overpasses, which can funnel the wind.
Do not waste time opening windows. It does not equalise pressure, and it wastes precious seconds.
Keep a battery radio, a charged phone, a torch, water and a first aid kit ready.
After the storm, stay away from fallen power lines, broken glass and damaged buildings.

Keep watching the sky and the forecast with the live weather, hourly forecast and weather maps on WeatherWorld.

Can We Predict Tornadoes?

Forecasters can tell days ahead when the ingredients for severe storms are in place, and they can issue a warning when radar shows rotation in a storm or when spotters see a funnel. The lead time is often only minutes, so a clear plan is vital. The exact time and place of a touchdown are still very hard to forecast far in advance.

Learn More

For official safety guidance, visit the National Weather Service tornado safety page. To understand how pressure differences drive severe weather, read about atmospheric pressure, and to see how the same atmosphere can clear after a storm, read how a rainbow forms.

Frequently Asked Questions

What is a tornado in simple words?

A tornado is a fast-spinning column of air that reaches from a thunderstorm cloud to the ground. It can destroy buildings and throw objects through the air.

How does a tornado form?

Warm, moist air rises in a thunderstorm while wind shear makes the storm rotate. The rotation tightens and stretches down from the cloud until it touches the ground.

How fast are tornado winds?

From about 105 km/h in weak tornadoes to over 400 km/h in the most violent ones.

What is the difference between a tornado and a funnel cloud?

A funnel cloud is a spinning cloud that hangs from the storm but has not reached the ground. When it touches the surface, it is a tornado.

How long does a tornado last?

Most last only a few minutes. A small number last longer than half an hour, and very rarely more than an hour.

Where is the safest place during a tornado?

The lowest level of a strong building, in an interior room away from windows, such as a basement or a small bathroom.

Can a tornado happen at night?

Yes. Night tornadoes are especially dangerous because they are hard to see and people may be asleep, so a weather alert on your phone or radio is important.

Final Thoughts

A tornado is one of the most violent and fastest-changing weather events on Earth. It grows from warm, moist air, an unstable atmosphere and winds that change with height, and it can go from nothing to a destructive funnel within minutes. You cannot stop a tornado, but you can prepare. Learn the warning signs, know where your safe place is and act at once when a warning is issued. A few minutes of preparation can save lives.

Stay ahead of severe weather: check the live weather, hourly forecast and weather maps on WeatherWorld.

What Is a Flash Flood and How Does It Happen?

October 25, 2026October 3, 2026 by admin

What Is a Flash Flood and How Does It Happen?

Weather Guide • Flood Safety • 7 minute read

A flash flood happens when heavy rain runs off the land faster than the ground or rivers can handle, so water rises within minutes or hours.

The sky is dark in the hills, but where you are standing the weather looks fine. A few minutes later a dry stream bed fills with brown, roaring water. That is a flash flood, and it is one of the most dangerous weather events because it gives so little time to react. So what is a flash flood, and how does it happen? This guide explains the science in simple steps, shows what makes some places more at risk, and tells you exactly how to stay safe.

The short answer: A flash flood is a sudden, fast-rising flood that usually starts within a few hours (often under six) of heavy rain, or from a dam or ice dam failure. It happens when water arrives faster than the ground can soak it up or rivers can carry it away. Steep land, hard surfaces and slow-moving storms make it worse.

What Is a Flash Flood?

A flash flood is a rapid rise of water in a normally dry area or in a small stream, river or drain. The word “flash” is the key. Unlike a river flood, which can build slowly over days as water collects far upstream, a flash flood can reach its peak in minutes to a few hours. The water is often fast, muddy and full of rocks, trees and debris, so it can destroy roads, bridges and houses.

Flash Flood vs River Flood

Feature	Flash flood	River flood
Speed	Minutes to a few hours	Many hours to days
Warning time	Very short, sometimes none	Usually longer
Where	Hills, valleys, dry channels, cities	Large rivers and flood plains
Water	Fast, powerful, full of debris	Slower, but may last for days
Main cause	Intense, short, heavy rain	Long rain or snowmelt upstream

How Does a Flash Flood Happen? 5 Steps

Intense rain falls. A thunderstorm or a monsoon cloudburst drops a large amount of rain in a short time.
The ground cannot absorb it. Soil can only soak up water at a certain speed. When rain falls faster than that, or the ground is already wet, the extra water stays on the surface. This is called runoff.
Water flows downhill and joins up. Runoff flows into gullies, streams and drains. Many small streams combine into one, so the flow grows quickly.
The channel fills. The narrow valley, stream or drain cannot carry that much water, so the level jumps up and spills over the banks.
A surge moves downstream. The flood can reach places where it is not even raining. People downstream may see a clear sky and still get hit by a wall of water.

What Causes a Flash Flood?

Heavy rain and slow-moving storms

A storm that moves slowly or keeps forming over the same place, called training, can drop huge amounts of rain on one area. Monsoon depressions and the remains of a tropical cyclone can also bring days of heavy rain.

Steep land

On steep slopes, water runs off quickly and has little time to soak in. Narrow mountain valleys act like funnels and make the flood deeper and faster.

Hard and dry ground

Concrete, asphalt and roofs do not absorb water. In cities, almost all the rain becomes runoff and pours into drains that may be blocked or too small. Very dry, baked soil and burned land can also repel water at first, so the rain runs straight off.

Saturated soil

If earlier rain has already filled the soil, a new storm cannot sink in at all, and even moderate rain can cause flooding.

Blocked drains and rivers

Rubbish, silt and buildings that block natural water channels cut the space water needs to flow away.

Dam, embankment or ice-dam failure

A broken dam, a breached canal bank or a collapsed natural dam made of ice or landslide debris can release a huge volume of water at once. In mountain regions, a glacial lake outburst flood (GLOF) happens when a lake of melted glacier water bursts through its ice or rock wall.

Snowmelt and rain together

Warm rain falling on a deep snowpack can melt it quickly, adding much more water than the rain alone.

Warning Signs of a Flash Flood

Heavy rain, thunder or dark clouds upstream or in the hills, even if it is dry where you are.
A sudden rise in the water level of a stream, or water that turns muddy, brown or full of debris.
A rumbling sound like a train or a roar coming from up the valley.
A dry stream bed that suddenly starts to flow.
Water rising in drains, underpasses and low roads.
An official flash flood watch or warning for your area.

Flash Flood Watch vs Warning

Alert	Meaning	What to do
Watch	Conditions could produce a flash flood	Be ready, check the forecast and plan an escape route
Warning	A flash flood is happening or about to happen	Move to higher ground at once

How Dangerous Is Moving Water?

People often underestimate the force of flowing water. As a rough guide used by safety agencies:

Depth of moving water	What it can do
About 15 cm	Can knock an adult off their feet
About 30 cm	Can float many cars
About 60 cm	Can carry away most vehicles, including large SUVs

You cannot judge the depth, speed or the state of the road under flood water by looking at it. The road may already be washed out beneath the surface. This is why safety teams say “Turn around, don’t drown.”

Flash Floods in Pakistan

Pakistan is highly exposed to flash floods. In the monsoon months from July to September, heavy bursts of rain on the steep hills of Khyber Pakhtunkhwa, Gilgit-Baltistan, Azad Kashmir and the Balochistan highlands can send water rushing down narrow valleys and dry hill torrents (called nullahs and rod-kohi channels) within hours. Hill streams near popular tourist areas such as Swat, Kaghan and Naran can rise fast, and tourists camping or taking photos on river banks are often caught by a sudden surge. In the north, glacial lake outburst floods are a growing concern as glaciers melt in a warming climate. The country’s monsoon floods of 2022 were among the worst in its history, affecting millions of people. In cities such as Karachi, Lahore and Rawalpindi, short, intense rain can fill blocked drains and nullahs and flood roads and underpasses within an hour. Always follow warnings from the Pakistan Meteorological Department and the National Disaster Management Authority (NDMA).

Flash Flood Safety Tips

Before the rain

Check the forecast and official alerts before travelling to rivers, hills, valleys and mountain resorts during the monsoon.
Know the nearest high ground and an escape route from where you live, work or camp.
Do not camp, park or stay in a dry stream bed, a river bank or a low area, even on a sunny day.
Keep a small emergency kit: drinking water, dry food, medicines, a torch, a power bank, a radio and copies of key documents in a waterproof bag.
Clear drains and gutters around your home, and move valuables to higher floors.

During a flash flood

Move to higher ground immediately. Do not wait for more instructions if the water is already rising.
Never walk, swim or drive through flood water. Just 15 cm of fast water can knock you down.
If your car is caught in rising water, leave it and move to higher ground if you can do so safely. A car can be swept away in seconds.
Stay away from bridges over fast water, river banks and drains.
Do not touch electrical wires, poles or appliances in or near water. Turn off the power if it is safe to do so.
Do not go back for belongings or to take photos.

After the flood

Return home only when officials say it is safe.
Avoid flood water. It can carry sewage, chemicals and sharp objects.
Boil or treat drinking water until it is declared safe.
Watch for damaged roads, weak walls, snakes and loose power lines.

Keep watching the sky and the forecast with the live weather, hourly forecast and weather maps on WeatherWorld.

Can Flash Floods Be Predicted?

Forecasters can often tell when the setting is right, for example when heavy rain is expected over steep land or already wet ground, and they issue watches. Radar and rain gauges help them issue a warning when a flood is happening or about to start. The difficulty is that the exact place and time of the heaviest rain are hard to predict. This is why you should take any warning seriously and not wait to see the water yourself.

Learn More

For official flood safety advice, visit the National Weather Service flood safety page. To understand how the same storms form, read about atmospheric pressure and what a tornado is, and see how a rainbow forms for the calm that often follows.

Frequently Asked Questions

What is a flash flood in simple words?

A flash flood is a sudden flood that rises very quickly, usually within a few hours of heavy rain. It can happen with little or no warning.

How does a flash flood happen?

Heavy rain falls faster than the ground can absorb. The extra water runs downhill, gathers in streams and drains, and rises quickly.

How fast can a flash flood happen?

It can start within minutes of heavy rain and reach its peak within a few hours. It can also arrive from rain that fell many kilometres upstream.

Can a flash flood happen when it is not raining?

Yes. The rain may be falling in hills far away, or a dam or ice dam may have failed. The water then reaches you under a clear sky.

Why are cities at risk of flash floods?

Roads and roofs do not absorb water, so almost all the rain runs off. Blocked or small drains cannot carry it away, and streets and underpasses flood.

What should I do if I am driving and see a flooded road?

Turn around and find another route. Do not drive through flood water, because the road may be damaged and the water may be deeper and faster than it looks.

What is the difference between a flash flood and a normal flood?

A flash flood rises within minutes to hours and is very fast and violent. A normal river flood builds more slowly, often over days, and gives more warning time.

Final Thoughts

A flash flood is a fast, powerful and often silent danger. It needs only heavy rain, steep or hard ground and a narrow path for the water. You cannot stop one, but you can stay out of its way. Check the forecast before you travel in the hills during the monsoon, keep away from streams and dry channels when rain is near, and move to higher ground at the first warning sign. Remember the simple rule: turn around, don’t drown.

Stay safe in heavy rain: check the live weather, hourly forecast and weather maps on WeatherWorld.

What Is Atmospheric Pressure?

October 25, 2026October 3, 2026 by admin

What Is Atmospheric Pressure?

Weather Guide • Everyday Science • 7 minute read

Atmospheric pressure is the weight of the air above us, and it changes with height and weather.

You have never felt it as a weight, yet atmospheric pressure is pressing on every centimetre of your body right now. It is so constant that we forget it exists, until we drive up a mountain and our ears pop, or until a weather forecaster says “falling pressure” just before a storm. This guide explains what atmospheric pressure is, how it is measured and how a few simple readings can help you predict tomorrow’s weather.

Think of the Air as an Ocean

The reason we are not crushed is that the pressure inside our bodies pushes outward with the same force. The pressure is balanced from every side, so we never notice it.

How Atmospheric Pressure Is Measured

Mercury barometer: a tube of mercury whose height rises and falls with pressure.
Aneroid barometer: a sealed metal capsule that expands and contracts slightly. It is the type found in wall barometers and many instruments.
Electronic sensor: the tiny chip found inside most modern smartphones, watches and weather stations.

Pressure Units Compared

Unit	Standard sea-level value	Where it is used
Hectopascal (hPa) or millibar (mb)	1013.25	Most weather forecasts and maps worldwide
Kilopascal (kPa)	101.3	Science and engineering
Inches of mercury (inHg)	29.92	Aviation and weather reports in the United States
Millimetres of mercury (mmHg)	760	Medicine and older instruments

Why Atmospheric Pressure Falls as You Climb

Height above sea level	Approximate pressure	Example
0 m	1013 hPa	Karachi coast
500 m	955 hPa	Islamabad area
2,000 m	795 hPa	Murree and the Galiyat
3,500 m	655 hPa	High mountain passes
5,500 m	505 hPa	Base camps of high peaks

These numbers are rough averages. Real values vary a little with the weather of the day.

Signs of Pressure in Daily Life

Your ears popping

Water boiling at different temperatures

Sealed packets that swell

Drinking through a straw

Highs and Lows on the Weather Map

Air pressure is not the same everywhere. Weather maps mark areas of higher pressure with an H and areas of lower pressure with an L.

High pressure: air slowly sinks and warms, which prevents clouds from forming. Skies are usually clear and winds are light. In winter, clear nights under a high can feel very cold, and in some regions they bring fog or smog.
Low pressure: air rises and cools, so moisture condenses into clouds. Expect cloud, wind and rain. The deeper the low, the stronger the weather.

Wind itself is air moving from high pressure toward low pressure. The bigger the difference over a short distance, the stronger the wind.

The deepest lows of all belong to storms. A very fast fall in pressure is also a warning sign of a tropical cyclone approaching a coast.

How to Read the Pressure Trend Yourself

A single number does not tell you much, but the direction and speed of change do. Most weather apps show pressure under the details of the forecast. Check it every few hours and compare.

What the pressure is doing	What it usually suggests
Rising slowly and steadily	Improving, settled weather
Rising quickly	Clearing skies, often with gusty wind
Steady	No big change soon
Falling slowly	Clouds increasing, a change within a day
Falling quickly	Storm, strong wind or heavy rain approaching

Why Weather Services Use “Sea-Level Pressure”

Atmospheric Pressure and the Seasons in Pakistan

Does Pressure Affect How You Feel?

Learn More

For a clear official explanation of how pressure shapes the weather, visit the National Weather Service JetStream guide to air pressure. To see how pressure and moisture work together, read how a rainbow forms, and to see how it affects the air you breathe, read what air quality is and how weather affects it.

Frequently Asked Questions

What is a normal atmospheric pressure reading?

Around 1013 hPa at sea level. In real life, values normally fall between roughly 980 and 1040 hPa.

Does low pressure always mean bad weather?

Often, but not always. It makes cloud and rain more likely, but the amount of moisture and other factors also matter.

Can my phone measure atmospheric pressure?

Many phones contain a barometer sensor, and some apps display the reading. It is good for watching trends.

Why is the pressure different in the hills?

There is less air above you at higher places, so there is less weight pressing down.

Final Thoughts

See what the air is doing: check the live weather, hourly forecast and weather maps on WeatherWorld.

What Causes Lightning and Thunder?

October 25, 2026October 3, 2026 by admin

What Causes Lightning and Thunder?

Weather Guide • Severe Weather • 7 minute read

Lightning is a giant electrical spark inside or from a storm cloud, and thunder is the sound made by the air it heats.

A bright white flash splits the dark sky, and a few seconds later a deep rumble rolls across the town. Every child asks the same question: what causes lightning and thunder? The answer is a mix of ice, air and electricity inside a storm cloud. Lightning is a huge electric spark. Thunder is the sound that spark makes as it blasts the air around it. This guide explains how a storm cloud builds up electric charge, why you see the flash before you hear the sound, and how to stay safe.

The short answer: Inside a thunderstorm, tiny ice crystals and soft hail rub against each other and separate electric charge. The top of the cloud becomes positive and the bottom becomes negative. When the difference becomes too large, a spark jumps across the gap. That spark is lightning. It heats the air to around 30,000°C in a fraction of a second, and the air bursts outward with a loud boom. That boom is thunder.

What Is Lightning?

Lightning is a sudden, powerful discharge of static electricity. It is the same kind of spark you sometimes feel when you touch a door handle after walking on a carpet, only enormously larger. A single bolt can be several kilometres long and carry a current of tens of thousands of amperes. Earth is hit by lightning roughly 40 to 50 times every second, and most of these flashes happen over land in the tropics.

What Is Thunder?

Thunder is the sound wave produced by lightning. The bolt heats a thin channel of air to about 30,000°C, which is several times hotter than the surface of the sun. The air expands explosively and then cools and contracts, sending a shock wave outward. Close up, thunder is a sharp crack or bang. From far away it becomes a long, low rumble, because the sound from different parts of the bolt reaches you at different times and bounces off hills and clouds.

How Does Lightning Form? 5 Steps

A tall storm cloud grows. Warm, moist air rises quickly and builds a towering cumulonimbus cloud. Water droplets are carried high enough to freeze.
Ice particles collide. Tiny ice crystals rise with the updraft, while heavier soft hail pellets (called graupel) fall. When they collide, electric charge is transferred between them.
The cloud separates its charge. The light ice crystals, which carry positive charge, are lifted to the top. The heavier graupel, which carries negative charge, collects in the lower part of the cloud. The ground beneath the storm becomes positively charged.
A path opens. When the electric field becomes strong enough, a faint channel of charge called a stepping leader moves down from the cloud in short jumps. A matching streamer reaches up from the ground, often from a tall object such as a tree, tower or building.
The bright flash. When the two meet, a huge current surges up the channel. This return stroke is the brilliant flash you see. A single flash often repeats several times in a few tenths of a second, which is why lightning can appear to flicker.

How Does Thunder Form?

The same flash that lights up the sky also heats the air around it almost instantly. The air has no time to move out of the way, so its pressure rises sharply and creates a shock wave. That wave travels outward as sound. Because sound moves far slower than light, you always see lightning first and hear thunder later.

Why Do We See Lightning Before We Hear Thunder?

Light travels at about 300,000 kilometres per second, so it reaches your eyes almost at the same moment the flash happens. Sound travels at about 343 metres per second in air, which is roughly one kilometre every three seconds. The gap between the flash and the bang tells you how far away the strike was.

Seconds between flash and thunder	Approximate distance	What it means
0 to 3 seconds	Under 1 km	Very close: take shelter at once
3 to 9 seconds	1 to 3 km	Dangerously close
10 to 30 seconds	3 to 10 km	Within strike range: stay indoors
30 seconds or more	10 km or more	The storm is farther away, but still watch it

To estimate the distance, count the seconds between the flash and the first rumble, then divide by 3. The result is the distance in kilometres.

Types of Lightning

Cloud-to-ground: the bolt that strikes the earth. It is the most dangerous type for people and buildings.
Intra-cloud: a flash inside one cloud. It is the most common type, and it lights up the whole cloud, which is sometimes called sheet lightning.
Cloud-to-cloud: a flash that jumps between two separate clouds.
Cloud-to-air: a bolt that leaves the cloud and fades into the clear air nearby.
Ground-to-cloud: a bolt that starts from a tall structure, such as a mountain-top tower, and rises into the cloud.

Lightning Myths and Facts

Does lightning never strike the same place twice?

It does. Tall, pointed or isolated objects are struck again and again. Some tall towers are hit many times in a single year.

What is “heat lightning”?

It is simply lightning from a faraway storm. The flash can be seen at night, but the thunder is too far away to be heard. It is not a different kind of lightning.

Can lightning happen without rain?

Yes. A bolt can strike several kilometres from the storm’s rain area, which is why people sometimes call it a “bolt from the blue”. If you can hear thunder, you are close enough to be struck.

Are rubber tyres or rubber shoes protection?

No. The protection of a car comes from its metal roof and body, which direct the current around the passengers and into the ground. Shoes offer no real protection.

Where and When Does Lightning Strike Most?

Lightning needs thunderstorms, so it is most common where warm, moist air rises strongly. This means tropical land areas, mountain slopes and places with strong afternoon heating. Storms are most frequent in the late afternoon and evening, when the ground has been heated all day, and in the warm months of the year.

Lightning and Thunder in Pakistan

In Pakistan, lightning is most common in the pre-monsoon and monsoon months, from about May to September, when the plains are hot and moist air arrives from the sea. Thunderstorms can form over the plains of Punjab and Sindh, the hills of Khyber Pakhtunkhwa and Kashmir, and the desert area of Tharparkar. People who work in open fields, herd animals, sit under isolated trees or shelter in small huts are especially at risk. Lightning also often comes with strong winds, hail and sudden heavy rain, so it is often followed by flash floods in the hills. Always follow warnings from the Pakistan Meteorological Department when a thunderstorm is expected.

Lightning Safety Tips

The best rule is simple: “When thunder roars, go indoors.” If you can hear thunder, you are within range of a strike.

Go into a strong building with a roof and walls, or into a hard-topped metal vehicle with the windows closed. Open shelters, sheds, tents and bus stops do not protect you.
Follow the 30-30 rule: if the gap between flash and thunder is 30 seconds or less, go inside. Wait 30 minutes after the last thunder before going out again.
Stay away from windows, doors, and plumbing. Avoid showers, baths and washing dishes during a storm, because the current can travel through pipes.
Unplug sensitive electronics, or use a surge protector, and avoid using corded phones.
If you are caught outdoors, move away from open fields, hilltops, water, and isolated trees. Do not shelter under a lone tree, and do not hold a metal pole or umbrella.
Stay out of lakes, rivers, the sea and swimming pools. Water conducts electricity.
If a group is outside, spread apart so a single strike does not harm everyone.

If someone is struck by lightning

A person who has been struck does not carry any electric charge, so it is safe to touch them. Call for emergency help at once. If the person is not breathing, begin CPR and continue until help arrives. Many lightning victims survive when they receive help quickly.

Keep watching the sky and the forecast with the live weather, hourly forecast and weather maps on WeatherWorld.

Can Lightning Be Predicted?

Forecasters can tell when the atmosphere is likely to produce thunderstorms, and radar and lightning detection networks track storms as they move. They cannot say exactly where the next bolt will strike. That is why you should act on the first sound of thunder instead of waiting for the rain to start.

Learn More

For official safety advice, visit the National Weather Service lightning safety page. To see how the same storms can spin into something more dangerous, read what a tornado is and how it forms. To understand the pressure changes that come with storms, read about atmospheric pressure, and to see how big storms form over the sea, read what a tropical cyclone is.

Frequently Asked Questions

What causes lightning and thunder in simple words?

Ice particles in a storm cloud rub together and build up electric charge. When the charge becomes too strong, it jumps as a spark, which is lightning. The spark heats the air so fast that it booms, which is thunder.

Why do we see lightning before we hear thunder?

Light travels much faster than sound. The flash reaches you almost instantly, while the sound takes about three seconds to travel each kilometre.

How hot is lightning?

A lightning channel can reach about 30,000°C for a very short moment, which is several times hotter than the surface of the sun.

How far away can you hear thunder?

Usually about 10 to 15 kilometres. Beyond that, the sound fades or bends upward and is lost before it reaches you.

Can you be struck by lightning indoors?

It is rare, but possible through wiring, plumbing and corded devices. Staying away from water pipes and electronics during a storm lowers the risk.

Is it safe to use a mobile phone during a thunderstorm?

Using a mobile phone indoors is safe. Avoid corded phones and avoid using any device that is plugged in and connected to the wiring.

How long should I wait after thunder before going outside?

Wait at least 30 minutes after the last thunder you hear. Storms can still strike after the rain has stopped.

Final Thoughts

Lightning and thunder are two parts of the same event. Ice and air inside a storm cloud build up an enormous electric charge, the charge releases as a spark of lightning, and the heated air makes the sound of thunder. The science is fascinating, but the safety message is simple. If you can hear thunder, go indoors, stay there until 30 minutes after the last rumble, and keep away from water, open ground and tall isolated objects. A little respect for the storm can protect you and your family.

Stay safe in a storm: check the live weather, hourly forecast and weather maps on WeatherWorld.