Climate in Finland
The main factor influencing Finland's climate is the country's geographical position between the 60th and 70th northern parallels in the Eurasian continent's coastal zone, which shows characteristics of both a maritime and a continental climate, depending on the direction of air flow. The mean temperature in Finland is several degrees (as much as 10°C in winter) higher than that of other areas in these latitudes, e.g. Siberia and south Greenland. The temperature is raised by the Baltic Sea, inland waters and, above all, by airflows from the Atlantic, which are warmed by the Gulf Stream.
When westerly winds prevail, the weather is warm and clear in most of the country due to the 'föhn' phenomenon caused by the Keel range. Despite the moderating effect of the ocean, the Asian continental climate also extends to Finland at times, manifesting itself as severe cold in winter and extreme heat in summer.
Since Finland is located in the zone of prevailing westerlies where tropical and polar air masses meet, weather types can change quite rapidly, particularly in winter. The systems known to affect Finnish weather are the low-pressure system usually found near Iceland and the high-pressure systems in Siberia and the Azores. The position and strength of these systems vary, and any one of them can dominate the weather for a considerable time.
According to Köppen's climate classification, Finland belongs wholly to the temperate coniferous-mixed forest zone with cold, wet winters. The mean temperature of the warmest month is no lower than 10°C and that of the coldest month no higher than -3°C. Rainfall is moderate in all seasons.
Crown snow-load in Lapland.