Helsinki Climate Trends
Finland · Europe · 50 years of climate trend data
This page tracks how Helsinki's climate has shifted over 50 years of daily measurements, warmer summers, milder winters, and changes in rainfall, rather than current conditions. The two clearest signs of change: frost days have dropped by 34.2 a year, from 153.2 to 119 days below 0°C and the growing season has grown 30 days longer. Measurement period: the last 50 years (1976-2025).
Data through September 13, 2026.
Frequently asked questions about Helsinki's climate
How much warmer have summers in Helsinki become?
The average daytime high across June, July and August rose by 2.3°C between 1976-1980 and 2021-2025. That is a five-year average at each end rather than two isolated summers, so a single exceptional heatwave or cool summer does not drive the number.
Have winters in Helsinki become milder?
The average daytime high across December, January and February rose by 3.8°C between 1976-1980 and 2021-2025. In many capitals in this dataset winter is changing faster than summer, which shows up most clearly in the frost-day count below.
How many days above 30°C does Helsinki get a year?
Helsinki averaged 0 days a year above 30°C in 2021-2025, the same as 0 in 1976-1980. So the count of genuinely hot days has barely shifted here in 50 years, even where other figures on this page have.
How many frost days does Helsinki still get?
Helsinki averaged 119 frost days a year in 2021-2025, down from 153 in 1976-1980. Fewer frost days sounds pleasant, but water pipes, heat pumps and garden planting are all sized for a cold season that increasingly no longer arrives.
Is spring arriving earlier in Helsinki?
Spring now starts about 1.1 week earlier than in 1976-1980. The start point is the first day the trailing seven-day average high crosses 12°C, a fixed in-house measure used only to compare Helsinki against itself rather than against other cities.
Has the growing season in Helsinki grown longer?
The growing season is about 30 days longer between 1976-1980 and 2021-2025. That is the stretch between the start of spring and the first autumn night below freezing, which is exactly the window gardens, farming and pollen seasons run inside.
Is rainfall in Helsinki getting heavier?
Helsinki averaged 1.6 days a year with more than 20mm of rain in 2021-2025, up from 1.2 in 1976-1980. Warmer air holds more water vapour, so the same annual rainfall increasingly arrives in shorter, harder bursts, which loads drains and water storage more than the annual total suggests.
