Air pressure and weather

In short: Air pressure is the weight of the column of air above us, on average about 1013 hectopascals at sea level. High and low pressure areas determine the weather.

In more detail: When pressure falls, clouds and rain usually move in. When it rises, weather generally becomes steady and clear.

In detail

• High: Sinking air dissolves clouds. In summer sunny and warm, in winter often fog or frost.
• Low: Rising air cools, water vapour condenses. It turns cloudy, windy and rainy.
• Wind: Air flows from high to low. The Earth’s rotation deflects it.
• Altitude: Per 8 metres the pressure drops by about 1 hPa. That is why water boils earlier on a mountain (aggregatzustaende).
• Barometer: It measures pressure. A rapid fall often announces a storm.