Northern Europe is situated in the low pressure belt between the subtropical high and the polar high. In areas of the Atlantic Ocean that are south and southeast of Iceland the average atmospheric pressure is low and this directs southwesterly winds to Northern Europe. These southwesterly winds bring heat to northern latitudes in western Europe. Warm water transported by the Gulf Stream and North Atlantic Drift also contributes to this. Thus North Europe has, for its latitude, an unusually mild climate. At the same latitude as southern Norway but west of the Atlantic is southern Greenland, where most of the land is covered by an inland ice sheet.

In this climatic system, cyclones are generated that travel eastwards with rain that is enhanced when the cyclones meet the mountains of Scotland, Scandinavia and the Alps. The cyclones have a more northerly position in summer than in winter and the Mediterranean areas thus have drought during summer. In Northern Europe there is cyclonic rain in all the seasons, with a maximum in late summer and autumn. The other major source of precipitation is convective rain, especially during the warm season. On hot days the air near the ground is heated and becomes unstable so that warm air rises up through the atmosphere, is cooled, and liberates precipitation, often as thunderstorms. This is the most important source of rain in the eastern, more continental parts of Europe.