Weather locations in Finland

Finland lies between about 60°N and 70°N, well inside the Arctic, and occupies the western side of the Fennoscandian region between the Gulf of Bothnia and the Russian border. Much of the country is a low, flat shield of ancient rock covered with clay and moraine, rising only in the north-west to the mountains of Lapland. The weather turns on the contrast between warm, humid air coming from the south-west and the cold, dry continental air that settles over the interior in winter.

Main climate types

Almost all of Finland falls into the boreal, or subarctic, group of the Köppen classification, with mild summers and cold snowy winters. A narrow strip along the southern and south-western coast, in Uusimaa and around Turku, reaches a warmer temperate subtype with a slightly longer growing season. The north-west of Lapland is the coldest part, and the highest ground in the west has a montane variant.

Temperatures

Helsinki averages about minus 5 °C in January and about 18 °C in July; further inland, Jyväskylä averages about minus 6 °C in January. In Lapland the January mean drops to about minus 13 °C in the west and minus 15 °C or colder to the east. Summers are the opposite, with July means of about 18 °C on the south coast, about 15 °C in western Lapland and around 14 °C in the east. Cold spells below minus 20 °C are normal inland in January and February.

Rainfall

Annual totals are moderate by northern standards, about 640 mm in Helsinki, rising to 700 mm to 800 mm in the east and along the western slopes. Most rain falls in July and August, when humidity is highest. Between December and March precipitation falls as snow, and cover usually persists from late November to early April in the south and from October to late May in the north. The sun stays below the horizon for weeks in the far north in winter.

When to go

The summer, from late June to August, is the main season, with temperatures in the low 20s °C and long daylight. Late August and early September are warm and clear. For snow, skiing is best from January to March in the interior and the north.