RTÉ Weather

Weather

There are lots of different types of weather. You know that one day it can be sunny and the next day it can be rainy, sometimes it snows and on some days it's so foggy you can't see out the front door. But where does all this weather come from and why is it so different?

On this page I'll show you lots of different types of weather and I'll give you some examples of how the different types of weather can sometimes be very dangerous.

Wind

Extreme Fact: In 2005 Hurricane Katrina hit the coast of the United States. One of the most destructive hurricanes ever seen, Katrina had wind speeds of 175mph and covered most of New Orleans in flood waters.

Windy days can be great fun. The wind can blow leaves off tress and opens doors and windows, but remember don't try to put an umbrella up!

What is wind?

Wind is air in motion. As the sun warms the Earth's surface, the atmosphere warms too. Some parts of the Earth receive direct rays from the sun all year and are always warm. Other places receive indirect rays, so the climate is colder. Warm air, which weighs less than cold air, rises. Then cool air moves in and replaces the rising warm air. This movement of air is what makes the wind blow.

There are lots of different strengths of winds, from a light breeze, where the air travels at around 4 mph to a hurricane where the air travels faster than 70 mph.

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Rain

Extreme Fact: In Ireland despite the term "April Showers" April is actually the driest month generally. The wettest months almost everywhere are December and January.

Rainy days make everything fresh and clean. They help plants to grow and make lots of puddles to play in. The rain helps plants to grow by giving them lots to drink. Although cows don't really like to get wet, we don't mind the rain as we know it will help the yummy grass to grow and will help us to produce lots of lovely milk. Did you know that some people say that cows can tell if it's going to rain because they lie down when they feel rain coming? So next time you're going out and you see a field full of cows all lying down, remember to bring an umbrella.

What is rain?

Rain comes from clouds. Water droplets form from warm air. As the warm air rises in the sky it cools. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.

Rain drops aren't as big as most people think, they are actually smaller then a centimeter and without any wind, they fall at between 7 and 18 miles an hour depending on their size.

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Clouds

Types of Clouds: There are lots of different types of clouds, here are a few of them. High Clouds are called Cirrus, these are usually found about 18,000 feet in the air. Middle Clouds are called Alto, these are found 6,500 to 18,000 feet in the ait. Low Clouds are called Stratus, these are found below 6,500 feet in the air.

From white and fluffy to dark and rainy, clouds have a big impact on the kind of weather we have every day.

What is a cloud?

A cloud is a large collection of very tiny droplets of water or ice crystals. The droplets are so small and light that they can float in the air. All air contains water, but near the ground it is usually in the form of an invisible gas called water vapor. When warm air rises, it expands and cools. Cool air can't hold as much water vapor as warm air, so some of the vapor condenses onto tiny pieces of dust that are floating in the air and forms a tiny droplet around each dust particle. When billions of these droplets come together they become a visible cloud.

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Sunshine

Extreme Fact: A total eclipse occurs when the sun is totally blocked from the earth by the moon. On August 11th 1999 a total eclipse was witnessed in Europe. The moon moved in front of the sun and darkness fell on the earth. During the eclipse only the light shining fromt he sun was visible and people gathered all over Europe to watch the spectacular event.

The sun is responsible for most of the earth's weather, even though it is 93 million miles away. It lights up the sky during the day and keeps everything on the planet warm. In the summer the earth is tilted towards the sun, so the days are warmer, brighter and longer. The suns rays are important in helping plants to grow. In the summer, because there is more sunlight, plants grow quicker and are lush and delicious. Cows love the summer because there is so much delicious grass around and that helps them produce lots of creamy milk.

What is sunshine?

The Sun is a star, 868,000 miles across, in the center of our solar system. The earth revolves around the sun and its intense heat gives energy to the earth's atmosphere and sets it in motion. The sun keeps everything on the planet alive and it affects all of the other types of weather.

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Thunder and Lightning

Extreme Fact: Around the earth there are 100 lightning strikes per second, or 8,640,000 times a day.

Thunder and lightning usually happen during a storm. To tell how far away you are from the storm count the number of seconds between when you see the lightning and when you hear the thunder. Divide this number by five and that is how many miles away the storm is.

What is lightning?

Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!

What is thunder?

Thunder is caused by lightning. When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel. Once the light is gone the air collapses back in and creates a sound wave that we hear as thunder. The reason we see lightning before we hear thunder is because light travels faster than sound.

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