August was record warm in some parts of the country
According to preliminary statistics of the Finnish Meteorological Institute, August was at least unusually war in almost the whole country, and even exceptionally warm in the area ranging from Uusimaa to eastern Lapland. Station-specific records were broken or equalled at 18 observation stations that have been measuring the temperature for at least 30 years. For example, August was the warmest in the 114 years of recorded history in Heinola and the 96 years of recorded history in Tohmajärvi.
The average temperature of the month varied from slightly over 19 degrees on the southern coast to about 12 degrees in the northwest of Finnish Lapland. The greatest deviation from the average for the statistical reference period 1991–2020 was in the southeast where temperatures were about three degrees above the average.
Hot temperatures were measured somewhere in Finland on a total of 19 days, which is more than double the average for August in the reference period 1991–2020. This many hot days in August were last recorded in 2006, when their number totalled as many as 27. The Hirvivaara observation station in Mäntsälä and Asemantaus in Heinola had the greatest number of hot days; 17 at both stations.
The highest temperature of the month, 31.7 degrees, was recorded on 16 August at the observation station at Pori railway station. The lowest temperature in August this year, –2.9 degrees, was recorded at Ylivieska airport on the 31 August.
August saw the least precipitation in the recorded history of Helsinki-Vantaa airport
Precipitation in August varied considerably within Finland. In the southern and eastern parts of the country, the precipitation levels in August were unusually low in many areas. When compared with the usual precipitation levels, the driest place was Helsinki-Vantaa airport, where August saw the least precipitation in the recorded history of the observation station. Areas near the western coast, on the other hand, saw unusually or exceptionally high levels of precipitation. For example, in Teuva, August was the rainiest in the 108-year history of the station.
According to preliminary results, the Kärjenkoski observation station in Isojoki had the most precipitation for the month, 210.4 millimetres. The least precipitation was recorded at Helsinki-Vantaa airport, only 5.9 millilitres. The greatest amount of precipitation in a single day (from 9:00 am until 9:00 the following morning) was on 5 August: 90.9 millimetres, measured at Seinäjoki Pelmaa observation station.
A record number of lightning-strikes in August
After a quiet lightning period from May to July, August was record active. The number of cloud-to-ground lightning strikes in the whole month was 86,280, which is the highest total number of lightning strikes for August in the lightning statistics recorded from 1960 onwards. The previous record from 1972 was exceeded by more than 1,200 lightning strikes. In addition, on 19 August, 34,183 cloud-to-ground lightning strikes were located in our country during a 24-hour period, which is the highest number since the operation of the lightning location network began in 1998. However, a 24-hour record can be found in the period preceding 1998, approximately 40,000 lightning strikes counted on 29 June 1988.
The number of sunshine hours in August varied from 140 hours in Lapland to approximately 300 hours on the southern coast. The number of sunshine hours was higher than usual; exceptionally high in some places.
The summer was 1–2 degrees warmer than usual
The average temperature of the whole summer (June–August) varied from approximately 12 degrees in the northwest of Lapland to approximately 18 degrees in the south of the country. The summer was unusually warm in a large part of the country, even exceptionally warm in the east of Lapland. The record for the warmest summer in the recorded history was broken or equalled at four stations: Salla Värriötunturi, Sodankylä Lokka, Kuusamo airport and Saariselkä travel centre in Inari.
The highest temperature of the summer was 32.9 degrees, which was recorded at Pori airport on 28 June. The lowest temperature, -2.9 degrees, was recorded at Ylivieska airport on 31 August. In the June-August period, Finland saw a total of 42 hot days on which the temperature exceeded 25 degrees; the long-term average is 33 hot days. In addition, there was one hot day in May. Of the individual observation stations, the greatest number of hot days in the June-August period, 34 days, was recorded at Asemantaus observation station in Heinola.
A lot of regional variation in precipitation
There was plenty of variation in precipitation levels in the summer. There was generally more precipitation than usual in central and northern Finland; the summer was even exceptionally rainy in Ostrobothnia and South Ostrobothnia. The southern part of the country saw less precipitation than usual, precipitation levels were even unusually low in some places.
According to preliminary data, the precipitation was the highest at Kärjenkoski observation station in Isojoki, where the rainfall was 361.9 millimetres in the June-August period. The least precipitation was recorded at Kotka Rankki observation station, 71.4 millimetres.
Between June and August, the number of cloud-to-ground lightning strikes was more than 155,000, which is over 32,000 more than typically within that time period.
The number of sunshine hours was higher than usual in the summer.
Climate statistics Weather statistics from Climate service tel. 0600 1 0601 (€ 4.01/min + local call charge)
Meteorologists use the word exceptional when a weather phenomenon occurs on average no more than once every 30 years. A phenomenon is called rare when it occurs less frequently than once in ten years, on average.