Uusimaa (Nyland in Swedish) is the southernmost region of Finland, wrapped around the Gulf of Finland and home to the capital, Helsinki. It combines a compact seaside capital, a UNESCO sea fortress, ancient forest national parks, and wooden-house towns such as Porvoo, Hanko, and Ekenäs, all within about two hours of each other by public transport.
Uusimaa has a humid continental climate moderated by the Baltic Sea (Köppen Dfb). Central Helsinki (Kaisaniemi, 1991-2020 normals) averages 9.6°C highs and 3.5°C lows over the year with 653 mm of precipitation. Winters are cold and dark (January mean -3.1°C, February highs -1.3°C), summers are mild and bright (July highs 21.9°C), and daylight ranges from about 6 hours in December to 19 hours in June. The coast is windier and cooler than inland forests such as Nuuksio.
Best time to visit
Best: Year-round
Avoid: None
Month-by-month weather
Typical conditions throughout the year.
January
-3.1°C/26°F
Cold, dark and snowy with about 6 hours of daylight. Sauna season, frozen sea walks and the last days of Lux Helsinki.
February
-3.8°C/25°F
The coldest month; the sea freezes near the shore, ski trails open in Espoo and Helsinki, and daylight grows quickly.
March
-0.7°C/31°F
Still wintry with melting snow and slush; sunshine rises sharply and daylight reaches about 12 hours by late March.
April
4.4°C/40°F
Raw spring with patchy ice and the first buds; the driest month (about 34 mm).
May
10.4°C/51°F
Spring bursts out with Vappu on 1 May and 14-17 hours of daylight; the best time before the summer crowds.
June
14.9°C/59°F
Bright 18-19 hour days and the white-night glow, Midsummer on the Friday between 19 and 25 June; the sea is still cold.
July
18.1°C/65°F
Warmest month with highs near 22°C and many hours of sun; many Finns are on holiday so the city is quiet and festivals run.
August
16.9°C/62°F
Warm and the wettest month (about 81 mm) with dark evenings returning; Flow Festival, Helsinki Festival and Helsinki Design Week.
September
12.3°C/54°F
Crisp and colourful with ruska (autumn colours) starting; the sea is still mild and crowds thin.
October
6.6°C/44°F
Dark and drizzly with 9°C highs and about 73 mm of rain; Linnanmäki, Seurasaari and many island attractions are closed.
November
2.4°C/36°F
Grey and damp, the darkest weeks, highs around 4°C and only about 36 hours of sunshine for the month.
December
-0.7°C/31°F
Christmas lights, markets, skating and snow; only about 6 hours of daylight.
The seasons
What to expect in each part of the year.
Spring
Months: Mar-May
Slush in March, daylight rising fast, 8.1°C average highs in April and 14.6°C in May (Kaisaniemi). April is the driest month at about 34 mm.
Summer
Months: Jun-Aug
Highs of 19-22°C, up to 19 hours of daylight and sea temperatures that warm to roughly 15-19°C by August. August is the wettest month (about 81 mm).
Fall
Months: Sep-Nov
Colourful September (15.4°C highs), wet and dark October (9.2°C, 73 mm) and grey November (4.4°C).
Winter
Months: Dec-Feb
Highs around 1°C in December and -1°C in January-February, snow cover, a frozen coast and only about 6 hours of daylight in midwinter.
Crowds & peak times
When to expect tourists and when to avoid them.
- High Season
- Jun-Aug (Helsinki is quieter in July because locals take holiday; Suomenlinna and Market Square are busiest on cruise-ship days); also December for Christmas markets
- Shoulder Season
- May and Sep (good weather, fewer visitors)
- Low Season
- Jan-Mar and Oct-Nov (dark, cold or wet, lowest hotel prices)
Major events & festivals
Time your visit around what matters.
Vappu (May Day)
Students don white caps and picnic in Kaivopuisto and Esplanadi; the Havis Amanda statue is capped on the evening of 30 April.
Helsinki Day
City birthday with free events across the centre.
Midsummer (Juhannus)
Finland's biggest holiday; many shops close and the city empties. Seurasaari Open-Air Museum holds a traditional Midsummer bonfire.
Helsinki Pride
Week-long festival ending with a Saturday parade (27 June in 2026).
Flow Festival
Urban music and art festival at Suvilahti in Sörnäinen.
Helsinki Festival
Concerts, theatre and performances across the city.
Helsinki Design Week
Design exhibitions and pop-ups across the city.
Tuomaan Markkinat (St. Thomas Christmas Market)
Traditional Christmas market on Senate Square; check dates each year.
Lux Helsinki
Light-art festival lighting central Helsinki.