Science of the skies: Weather fronts

Find out what weather fronts are and the types of changes in the weather that warm, cold and occluded fronts often bring.

LIFE Photo Collection

Why are they called Weather Fronts?

Weather Fronts were named just after WW1 to describe the battleground between two air masses when they meet.

1987 Storm Chart vt 0100 GMT on 16 October 1987 (1987-10-16/1987-10-16) by Met OfficeMet Office

What is a front?

A front is the boundary between two air masses which have different temperature and humidity. Where they meet there are often dramatic changes in the temperature and the weather. The greater the difference between the air masses the more intense the weather brought by the front. 

Weather Fronts by Met OfficeMet Office

There are three main types of weather front

Warm Fronts: semi-circle (half sun) symbol 
Cold Fronts: triangle (icicle) symbol
Occluded Fronts: a combination of both symbols. 

Warm Fronts

A warm front means that warm air is replacing colder air at the surface.

Cold Fronts

A cold front means that cold air is replacing warmer air at the surface.

Occluded Fronts

Occluded means 'hidden'. Occluded fronts happen when a cold front catches up with a warm front and lifts the warm air up effectively hiding it from the surface. 

OPHELIA (1)Met Office

Satellite and Radar Imagery

Since the arrival of satellite and radar imagery the theory of how weather fronts form has changed but fronts are still drawn onto weather fronts in the same way.

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