Front: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Facts

Also Known As	air front • frontal zone

Photos and Videos

Four-panel weather map sequence showing the progression of a cold front across North America over four days in January. Each panel marks cold fronts, warm fronts, air masses (continental Arctic, maritime tropical, maritime polar), high- and low-pressure centers, isotherms for 32 degreesF and 0 degreesF, areas of precipitation, and the shifting positions of weather systems as the cold front advances southeastward.

Thematic world map showing the frequency of thunderstorms by region, with color shading indicating average days per year of thunderstorm occurrence. Highest frequencies-marked in red and orange-are concentrated in central Africa, northern South America, and parts of Southeast Asia, while most other regions experience fewer thunderstorms, shown in lighter greens and yellows.

Diagram showing divergence and convergence zones around the polar front jet, with a yellow jet core arrow moving eastward from the Gulf of Mexico to the Atlantic Ocean. Colder air and convergence appear poleward, warmer air and divergence equatorward, illustrating atmospheric patterns.

Explore what happens when cold and warm air masses collide

See All Videos and Images →

Topics

stationary front occluded front warm front Cold front Equatorial front Polar front squall line Air mass Maritime air mass Continental air mass Polar air mass

Key People

default image

Tor Harold Percival Bergeron

Scandinavian meteorologist

rain. Child in the rain, wearing a rain coat, under a yellow umbrella. April Showers weather climate rain storm water drops

April Showers to March’s Lions and Lambs

Umbrella colored like a rainbow sticking out above a sea of black umbrellas while it rains. (storm, weather)

Weather Words Vocabulary Quiz

Lightning over a farm field. Weather electricity thunderstorm light energy tree

Facts You Should Know: Weather Quiz

Iceland, Glacier lagoon (Jokulsarlon)

Winter Weather Words Quiz