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Weather and Climate - Pressure

<Back to Weather and Climate

What is pressure?

Pressure is the weight of air pressing down on the earth's surface. Pressure varies from place to place and and results in pressure systems.

What is low pressure?

At times of low pressure the air is usually rising. As the air rises, it cools, condenses and forms clouds. Areas of low pressure are known as depressions.

Depressions occur when warm air meets cold air. The point where warm air meets cold air is called a front. Along the front there is usually cloud and rainfall. This occurs because the warm air cools and condenses when it meets the cold air (you can find out more about frontal rainfall here).

Depressions, or 'lows', bring rain, strong winds and changeable conditions. Changeable weather is a feature of British weather, depressions are responsible for much of this.

Strong winds blow in an anti clockwise direction.

What is high pressure?

Areas with above average pressure are called anticyclones. Anticyclones occur when air is sinking. As a result there are usually few clouds in the air. In the UK anticyclones bring cold clear days in winter and hot and sunny days in summer.

Light winds blow in a clock wise direction.


GeoNet is not responsible for the content of any of these sites

[Met Office]
An excellent leaflet covering the main aspects of weather charts and systems by the met office.

[BBC Weather]
Information on weather systems by the BBC.

 
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GeoNet is not responsible for the content of any of these sites

[Met Office]
An excellent leaflet covering the main aspects of weather charts and systems by the met office.

[BBC Weather]
Information on weather systems by the BBC.
 


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