June weather: severe night frosts and a heat wave
According to statistics of the Finnish Meteorological Institute, June was 1-2 degrees warmer than usual in most of the country. The greatest deviations were observed in the southwest archipelago and in the Åland Islands, where the average temperature was two degrees higher than normal, which can be seen as rare. In northern parts of the country the average temperature varied between 10 and 15 °C and in other areas the variation was 14–17 degrees.
The early days of the month was unusually chilly. At some observation stations, occurrences of night frost, when the temperature at ground level falls below freezing, set new records for June.
After the cold start, hot conditions dominated later in June. Starting from 12 June, high temperatures of 25.1 degrees or more occurred somewhere in the country every day. In a typical June, such levels of heat are reached on eight days of the month, but this year the hot-weather threshold was crossed on 19 days. The number of hot days was above average in almost all parts of Finland. In western and southern parts of the country the number of hot days was unusually, or exceptionally high. On two days, the temperature exceeded 30 degrees.
The highest temperature for June, 31.6 degrees, was recorded in Kankaanpää at Niinisalo Airport on the 20th of the month. The lowest temperature for June, -7.7 degrees, was recorded at Saana Fell in Kilpisjärvi on the first of the month. It was the lowest temperature ever recorded in June in the history of keeping records in Finland.
There was less precipitation than usual in June in nearly all areas. In many parts of the west and north, precipitation was less than half of the long-term average level for June. Helsinki-Vantaa Airport had the lowest precipitation level ever recorded for the month – 5.6 millimetres. Higher than average precipitation was recorded mainly in parts of North Karelia.
The location with the greatest amount of precipitation was Lampela in Lieksa, which got 149.1 millimetres of rain. The least precipitation for June was recorded at the Kumpula observation station in Helsinki – 2.6 millimetres. The highest amount of rain measured in a single day was 55.7 millimetres at the Möksy Observation Station in Alajärvi on 22 June.
More sunshine and lightning strikes than usual
There were more hours of direct sunlight than usual in much of the country. On the south coast and in the archipelago, the amount of sunshine was unusually or exceptionally high (370–420 hours).
The beginning of the month continued what had been a period of low thunder activity, but at the end of the month, on 28 June more than 10,000 cloud-to-ground discharges, and more than 9,000 on 29 June. The total number of cloud-to-ground discharges for the entire month was 43,500. The average number of cloud-to ground discharges for the normal period for June is about 34,500.
Meteorologists call a weather phenomenon exceptional when its statistical occurrence is three times or less in 100 years on average. A phenomenon is seen as rare when it occurs less frequently than once every ten years on average.
Weather statistics from the Climate Service, tel. 0600 1 0601 (€ 4,01/min + local network fee)