Weather

Weather can make the same place look very different at different times. During spring, this town has blue skies and dry ground.

During winter, this town now has snow on the ground, and the sky is overcast (meaning it is completely covered by clouds).

Weather is the day-to-day or hour-to-hour change in the atmosphere. Weather includes wind, lightning, storms, hurricanes, tornadoes, rain, hail, snow, and lots more. Energy from the Sun affects the weather. Climate tells us what kinds of weather usually happen in an area at different times of the year. Changes in weather can affect our mood and life. We wear different clothes and do different things in different weather conditions. We choose different foods in different seasons, like ice cream in the summer, nut and berries in autumn, or hot chocolate in the winter.

Weather stations around the world measure different parts of weather. Ways to measure weather are wind speed, wind direction, temperature, barometric pressure, and humidity. People try to use these measurements to make weather forecasts for the future. These people are scientists that are called meteorologists. They use computers to build large mathematical models to follow weather trends.

Bad weather can hurt people and their property. It can also just be a bother. Some examples of bad weather are:

• Tropical cyclones
• Rainstorms
• Drought
• Heat waves
• Frost
• Fog
• Tornadoes

Causes of weather

Weather happens because different parts of the Earth get different amounts of heat from the Sun. This makes different climates. The tropics get the most heat because the Sun shines straight down on them, while the poles get the least heat because the Sun shines on them from a low angle. Warmer air is lighter than cooler air and rises higher in the sky by convection.

The air always has some water mixed with it. This is called humidity. When it cools, the water can change from a gas to a liquid through condensation. Then the water can fall from the sky as rain or snow. After the air rises, it gets colder and goes back towards the ground. Because the air lost its water before, it is dry when it comes back to the ground. When two air masses of different temperatures meet, this is called a warm front or cold front.The ways that the air moves around the Earth are called atmospheric circulation.

Other websites

• Weather
• Internet Geography's weather page
• The Weather Channel