Weather

The Earth revolves around the Sun.

The tilt of the Earth's axis is the most important reason why seasons occur. The Earth's movement around the Sun causes seasons. The Earth is always tilted to one side as it orbits the Sun. So, when the North Pole tilts towards the Sun, it's summer in the northern hemisphere and winter in the southern hemisphere. When the South Pole tilts towards the Sun, it's summer in the southern hemisphere and winter in the northern hemisphere.

The four seasons of the year are spring, summer, autumn (fall) and winter

Spring

Spring is the season between winter and summer. During spring, temperatures gradually rise. In the spring, seeds take root and vegetation begins to grow. The weather is warmer and often wetter.

The term “weather” refers to the temporary conditions of the atmosphere, the layer of air that surrounds the Earth. We usually think of weather in terms of the state of the atmosphere in our own part of the world.

There are six main components, or parts, of weather. They are temperature, atmospheric pressure, humidity, clouds, precipitation, and wind. Together, these components describe the weather at any given time. These changing components, along with the knowledge of atmospheric processes, help meteorologists—scientists who study weather—forecast what the weather will be like in the near future.

Clouds can affect the amount of sunlight reaching the Earth’s surface. Cloudy days are cooler than clear ones because clouds prevent more of the sun’s radiation from reaching the Earth’s surface. The opposite is true at night—then, clouds act as a blanket, keeping the Earth warm.

Wind is the movement of air, caused by the uneven heating of the Earth by the sun and the Earth's own rotation. Winds range from light breezes to natural hazards such as hurricanes and tornadoes. Windsocks indicate the relative speed and direction of the wind in a specific place.

An anemometer is an instrument that measures wind speed and wind pressure.

Winds are formed when the Sun warms up Earth’s surface and the air above it. The warm air begins to rise, and new air flows to fill the space left by it. This flow is the wind.

Winds often lower the air temperature, as the new air that flows to replace warm air is usually cold. The flow of air itself also has a cooling effect. You can try this yourself by blowing air on the back of your hand.

Winds can sometimes be dangerous, especially in shore areas. Storms can make trees fall down and cause damage to buildings. The scientists that focus on studying and predicting the weather, meteorologists, try to warn people about storms and other dangerous weather conditions by issuing wind and storm warnings. In the summer, storms are often connected to thunder showers.

Wind speed is measured in metres per second (m/s). This unit describes how many metres the wind travels during the course of one second.

Meteorologists are scientists that study and predict the weather. They make weather observations on different time scales and compare their observations with various weather prediction models. These models are based on weather data gathered over the course of long periods of time. Sometimes, weather can behave in unexpected ways and cause the prediction to be wrong.

Specialised equipment such as rain radars are used to make short-term weather predictions. Rain radars measure the movement of rain clouds and compare this with observations about wind speed. As a result, the meteorologist can predict when and where it will rain. These predictions are often quite reliable.

You can find meteorological weather predictions on the internet, in newspapers and on the radio and television. You can also try to predict weather yourself by making observations about various weather phenomena. For example, tall and dark clouds often indicate approaching rain fronts.