why do we get rain when a front moves in?
Transcript: Transcript - Why does it rain? Frontal rain. Frontal rain occurs when two air masses meet. When a warm air mass meets a cold air mass, they don't mix as they have different densities (a bit like oil and water). Instead, the warm less dense air is pushed up over the cold dense air creating the 'front'. As a result, much like when air is forced up over mountains, the warm less dense air cools, and the water vapour condenses into water and falls as raindrops. This type of rain can happen anywhere in the UK. Orographic rain