Well the surface of the Earth varies in shape and consistency and includes mountains, plains, canyons, deserts, forests, lakes and seas. They all absorb sunlight to different degrees, leading to local temperature differences. In warmer areas the hot air expands and rises, causing a decrease in air pressure. The surrounding air, which is at a higher pressure, is sucked in to replace the rising air. It is a common occurrence at the seaside. During the day the land and the air above it heats up more than the sea, drawing the cooler sea air over the land in an onshore breeze. So now you know.
But what about the UK’s wind direction?
In the UK the most common winds (known as the prevailing winds) are from the west or south-west. These winds arrive in Britain after crossing the Atlantic Ocean, from which they pick up moisture. This air rises as it reaches higher ground, cools and falls as rain.
Is that why we get so much rain?
Many people believe that it rains a lot in the UK, but in fact its rainfall is similar to that in other European countries. Rainfall is evenly spread during the year, so even in summer we experience some wet weather. In spring and autumn there are likely to be some heavy showers, often followed by sunshine. In winter the rain is usually lighter but may last for longer. In the summer if there are a few days of particularly hot weather these are often followed by a thunderstorm.