Seasons in Finland

Winter

In winter the temperature remains below 0°C.

Winter usually begins in mid-October in Lapland and during November in the rest of Finland, though not until December in the southwestern archipelago.

Taking about two months for winter to proceed from Lapland to Åland.

Winter is the longest season in Finland, lasting for about 100 days in southwestern Finland and 200 days in Lapland.


Permanent snow covers open grounds about two weeks after winter begins. The snow cover is deepest around mid-March, with an average of 60 to 90 cm of snow in eastern and northern Finland and 20 to 30 cm in southwestern Finland.

The lakes freeze over in late November and early December. The ice is thickest in early April, at about 50 to 65 cm. 

The coldest day of winter is usually well after the winter solstice, at the end of January.

The coldest temperatures in winter are from -45°C to -50°C in Lapland and eastern Finland;

from -35°C to -45°C elsewhere;

and -25°C to -35°C over islands and coastal regions.

The lowest temperature recorded in Helsinki is -34.3°C (1987). The lowest temperature recorded at any weather station in Finland as of 2010 is -51.5°C (1999).

Spring

Spring begins a month earlier in the south than in the north, in April. Its duration ranges from 45 to 65 days.

For the real growing season to begin the snow must melt. Open areas lose their snow cover within two to three weeks of the beginning of spring, whereas on average the snow in the forest smelts about two weeks later.

The lakes usually become ice-free soon after the growing season begins in April in southwestern Finland, in May in the interior and in June in Lapland.

Summer

Summer usually begins in late May in southern Finland and lasts until mid-September.

The warmest day of the year comes about one month Midsummer, i.e. around July 20, in the whole of Finland.

The highest summer temperatures in the Finnish interior are from 32°C to 35°C.the highest temperature ever recorded in Helsinki is 31.6°C.

The highest temperature ever recorded was on July 29th, 2010, when 35°C was exceeded in several places (the maximum being 37.2°C in Joensuu). 

Autumn

Autumn begins around the last week of August in northern Finland and about one month later in southwestern Finland.

The growing season ends in autumn when the mean daily temperature drops below 5°C. This occurs around the last week of September in northern Finland and in late October or early November in southwestern Finland.

Thus the average length of the growing season is 180 days in the southwestern archipelago, 140 to 175 days elsewhere in southern and central Finland and 100 to 140 days in Lapland.

The first snow falls in northern Finland in September and elsewhere in October.