Helsinki Weather Overview:
Helsinki’s weather should be mainly continental in nature but the effect of the Baltic Sea and the Gulf Stream softens the temperatures throughout the year giving the city milder winters and cooler summers, a factor that’s best seen when comparing the city’s climate to others more inland in the country.
All Time Highs and Lows:
Helsinki’s hottest temperature was 34.1C which was recorded in July 2010 whilst the lowest the city has seen was -34.3 experienced in January 2010, just six months beforehand.
Helsinki is described by the Koppen classification model as having a hemiboreal humid continental climate, distinguished from a continental one by the influence of the sea and the Gulf Stream. This means mild winters when compared to other cities at this latitude and cooler summers.
Spring: You’d barely believe that spring had started as March still endures temperatures of below zero during the day. Spring comes late therefore and even in May you might shiver in temperatures barely making it to double figures. March has only four hours a day of sunshine on average but by the end of May, the effect of the northerly location and the rapidly lengthening of days mean that over nine hours a day are common.
Summer: Summer in Helsinki is best typified by the weather in June and July for by the time August is with you, daylight and sunshine hours are less than those of May and the temperature, particularly at the end of the month is reducing rapidly from the July peak. Rainfall in the summer is greater than in spring but increases as autumn approaches.
Autumn: Autumn comes quickly and you’ll soon feel a chill in the air, more so in the evenings. September can be pleasant but with an increase in rainy days and the amount of rain, a break there in October can be easily spoiled. November sees the first snowfall of the winter and whilst it may not last long, it’s a portent for the winter.
Winter: Unless you love cold snowy weather, winter in Helsinki is not for most. Temperatures are almost always below freezing and around ten inches of snow can be expected each month which, with the low temperatures experienced, accumulates substantially. It’s dark and gloomy for much of the season and on cloudy days, it almost seems like it doesn’t actually get light. December averages under an hour of sunshine a day.
Best Time of Year to Visit:
Helsinki in the summer, especially around the solstice is a wonderful experience. The days are long and often sunny although the occasional rainstorm can come as a surprise.