The average temperature in May was below the long-term average – the entire spring was exceptionally warm on the southern coast
Photo: Shutterstock.According to the statistics of the Finnish Meteorological Institute, the average temperature in May varied from just over 9 degrees Celsius in the southern part of the country to just under 4 degrees Celsius in Northern Lapland. The average monthly temperature in Lapland was 0–1 degrees higher than average, while the deviation in other parts of the country was 0–1 degrees lower than average in general.
The average temperature for the whole country in May was 7.4 degrees Celsius, which is 0.3 degrees Celsius lower than the average for the 1991–2020 reference period. The last time Finland experienced a cooler May was in 2021. May 2025 was also the first month since April 2024 when the monthly average temperature remained below the average for the 1991–2020 reference period.
The month’s highest temperature, 23.0 degrees, was recorded on 25 May at the Pötsönvaara observation station in Ilomantsi. The month’s lowest temperature, –10.4 degrees, was recorded on 5 May at Enontekiö Airport.
Precipitation near typical levels, high snowfall in northern parts of the country early in the month
Precipitation in May was mostly normal or slightly higher than usual. Precipitation was lower than normal mainly on the southern coast, in southern Lapland and in the Käsivarsi region of Lapland.
The highest precipitation in May, 81.0 millimetres, was recorded at Välikangas observation station in Kuusamo. The largest amount of precipitation in a single day, 41.1 millimetres, was recorded at Mehtäkylä observation station in Kalajoki on 2 May. The smallest amount of precipitation during the month was recorded at Kaaresuvanto observation station in Enontekiö, where precipitation was only 7.0 millimetres.
At the beginning of the month, snow depth in Central and Northern Lapland was generally over 50 centimetres, and over 120 centimetres in Kilpisjärvi. On 3–5 May, snowfall in some parts of the area extending from Kainuu to the eastern part of Lapland was exceptionally high for the time period.
On the last day of the month, snow depth was 33 centimetres at Kilpisjärven Kyläkeskus observation station in Enontekiö, and this was the only place in Finland with snow cover.
A slow start to the thunderstorm season
Ground discharges of lightning numbered only 865 in May. This is clearly less than the average for 1991–2020: the average number of lightning strikes in May is 6,600. The last time there were less ground discharges of lightning was in 2020.
The number of sunshine hours was less than usual in May. The total number was approximately 160–240 hours, and approximately 280-300 hours on the western coast and in the Southwest Archipelago.
Spring was warmer than normal, even exceptionally warm on the southern coast
The Finnish Meteorological Institute statistics showed that the average temperature for the entire spring, i.e. March-May, varied from just under 6 degrees Celsius in the southern part of the country to approximately –3 degrees in the Käsivarsi region of Lapland. The spring was warmer than usual in nearly all parts of the country, with only Northern Lapland remaining close to the normal average temperature. Spring was unusually warm in western Finland, and even exceptionally warm on the southern coast.
For example, the average spring temperature of 5.5 degrees in Russarö, Hanko was – along with spring 2016 – the highest in the 153-year history of that station. In Hanko, a spring this warm is approximately 60 times more likely in the current climate and 2.3 degrees warmer than without climate change.
Much of the country had less precipitation than usual this spring. Places with more precipitation than normal were mainly located in South and North Karelia and Northern Lapland. The highest precipitation recorded during the spring was 145.4 millimetres at Paljakka observation station in Puolanka. The lowest amount of precipitation was 36.9 millimetres recorded at the Kaaresuvanto observation station in Enontekiö.
Further information:
Weather statistics from the Climate Service on weekdays, tel. +358 600 1 0601 (€ 4.06/min + local network fee)