How climate change has warmed Finland’s winters since the 1960s | News
A comparison of the two 30-year periods shows that winter temperatures have risen sharply throughout Finland.
Last December was colder than usual. According to the Finnish Meteorological Institute, the month was exceptionally cold at a few coastal stations. December is only so cold in Finland about once every ten years.
Mild in the second week of January föhn the westerly winds brought melting. And last June was exceptionally hot highest average temperatures never recorded in parts of northern Finland.
However, climate change is not measured in individual days, months or even years. According to the guidelines of the World Meteorological Organization (WMO), climate statistics must be calculated from weather statistics for at least 30 years.
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The Finnish Meteorological Institute also considers the three-decade period to be long enough to detect fundamental fluctuations. While the analysis of the 2021 data is still ongoing, its most recent reference period is 1991-2020. Each 30-year data set contains approximately 2,700 days.
According to statistics, the average annual temperature in Finland has risen by about two degrees from the 1880s to the present day.
1991-2020 significantly warmer than 1961-90
Ylen meteorologist Anne Borgström has collected comparative data on winter temperatures in Finland for the last two 30 years – and the results are clear. The last period, 1991–2020, was considerably warmer than 1961–1990.
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For example, a study of the lowest temperatures in Helsinki in 1961 and 1990 shows that those 30 years had a total of 192 days between -12 and -14 degrees. In the following period (1991-2020), the number of such days dropped to 103.
In contrast, at its lowest point on the freezing point, there were slightly more than 300 days in the past, but well over 400 in the subsequent 30-year period. In other words, there were many more mild days.
Jyväskylä in central Finland has a similar trend as Helsinki. The number of days above zero has increased dramatically. The number of days between zero and two degrees of temperature has increased by more than 100. While there were only 77 days available for making snowballs in 1961-90, there were 182 in the next 30 years.
Record cold days in Finnish Lapland
There were plenty of cold days in northern Finland in Oulu in 1961–1990. At day 136, the lowest was between -24 and -26. In the most recent reference period, there were only 68 such days.
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In Sodankylä, Lapland, Finland, winter temperatures between -6 and -8 are considered rather mild. The number of such days has risen from 134 to 227.
In Sodankylä, on the other hand, reference data for the last three decades show one bitter cold day between -46 and -48 degrees and two days between -48 and -50 degrees. The data from 1961-90 do not contain such severe frosts.
As Borgström points out, climate change will not only bring milder weather but also more extremes.