The Three Types of Rainfall
Britain experiences three distinct types of rainfall, each caused by different weather conditions. Frontal rainfall occurs when warm and cold air masses collide, relief rainfall happens when air hits mountains, and convectional rainfall develops during hot summer days.
Frontal rainfall is what you'll see most often in the UK. When a warm front meets a cold front, the heavier cold air sinks whilst the lighter warm air rises above it. As this warm air rises, it cools down and condenses to form clouds that bring heavy rain.
Relief rainfall explains why western parts of Britain are so wet! Warm, moist air from the Atlantic Ocean hits our mountains and is forced upwards. The rising air cools and condenses into clouds, creating rainfall on the windward side of mountains. Once the air passes over the mountain, it warms up and descends, creating dry conditions called a rain shadow on the other side.
Convectional rainfall typically happens during summer when the sun heats the land intensely. This creates pockets of warm air called convection currents that rise rapidly. As they rise, they cool and condense into large cumulonimbus clouds that can produce heavy rainfall and thunderstorms.
Fun Fact: The lovely smell after rain has a special name - petrichor! Also, raindrops aren't tear-shaped like in cartoons - they're actually shaped like jellybeans and fall at about 14 mph.