Mean temperature change

Updated: 3 Dec 2018
Next update: 1 Mar 2019

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.


Autumn was warmer than average

Autumn (September-November) was 1-3 degrees warmer than on average in most of the country. This kind of warmth occurs on average once every 10 years, although the previous autumn with such warmth was in 2015.

The highest temperature in autumn was in Rauma on September 8th (26,1 °C). This was also the 64th and the last hot summer day of the year when temperatures exceeded 25 °C. This is only one day short of the most hot summer days in a year since the 1960. The most such hot summer days (65 in total) occurred in 2002.

The lowest temperature in autumn was -22,0 °C measured in Salla Naruska on November 27th.