Mean temperature change

Updated: 1 Sep 2021
Next update: 1 Dec 2021

Following the evolution of mean temperatures gives information on the progress of climate change. There are many factors that affect the temperatures. Annual and decadal temperature oscillations are related to changes in different weather types. Occasionally we get mild weather from southerly and westerly flows and occasionally colder weather from the north.

Finnish temperatures have risen approximately one degree Celsius since early 20th century. In Helsinki the urban heat island effect amplifies the warming trend. The temperature rise is not constant and it is partly obscured by the large natural variability which is characteristic for Finland. Globally however the temperature rise of over half a degree Celsius in the 20th century is statistically significant.


Summer was warmer than average

According to the statistics of the Finnish Meteorological Institute, mean temperature in summer (June-August) varied between over +18 degrees Celsius
in southern part of the country and about +13 degrees Celsius in northern Lapland. Summer was record warm in numerous observation stations in the southern
and central part of the country, for example the mean temperature in Helsinki Kaisaniemi, 18,9 degrees Celsius, was the station's highest in the measurement
history that starts from 1844. In the northern part of the country, however, summer was only unusually warm. The mean temperature of the summer for the whole
country was second highest in the records that start from early 1900's, the warmest summer being in year 1937.

The highest temperature this summer, +34,0 degrees Celsius, was measured in Heinola Asemantaus on July 15th. The lowest temperature, -3,6 degrees Celsius,
was measured in Salla Naruska on August 27th.

A total of 50 hot days were observed during the summer, whereas the long term average is 33. Out of all the individual observation stations, most hot days
were observed in Kouvola Anjala, a total of 42 days. In Anjala, 31 consecutive hot days were observed between June 18th and July 18th, which makes it the
longest period of consecutive hot days in record since 1961, when the records began.