December was mild with high precipitation levels
Across the majority of the country, December was very mild and marked by high precipitation, with the average temperature approaching normal levels only in Northern Lapland. Temperatures in 2017 were slightly higher than average in nearly all of the country and precipitation levels were unusually high, especially in parts of Southern Finland.
Photo: Olavi Alatalo
According to statistics from the Finnish Meteorological Institute, December saw in many places unusually high precipitation, especially in southern and central parts of the country, where some municipal precipitation records were broken. Precipitation levels crossed the 100 mm mark in wide areas of Southern and Central Finland. The month's highest precipitation level, 140.6 mm, was recorded in Kumpula, Helsinki. It remained , however, clearly below the highest monthly level for December ever recorded (189.6 mm), which was recorded in Kemiö in 2011.
In southern areas, the precipitation fell mostly as rain. In contrast, the country's central and northern parts saw mainly snowfall, which meant that the depth of snow in these areas was higher than average by the end of the month. In northern areas, the snow was over half a metre deep in many places.
The average temperature for December varied from 3 °C in southern and south-western coastal areas to below -10 °C in Northern Lapland. The highest temperature deviation for the month was observed in the east of the country, where the temperature was in places 5 °C higher than average. Elsewhere, December temperatures were in many places between 2 and 5 °C higher than average. Only in the most northern parts of Finnish Lapland was the temperature either close to the average or slightly below average. In December, both the highest and the lowest temperature was recorded on the 7th: the highest at 7.2 °C in Kökar and the lowest at -33.5 °C in Väylä, Inari.
Last year was slightly warmer and rainier than average
The average temperature in 2017 ranged from +6 °C on the south-west coast to around -1.5 °C along the north-west arm of Finnish Lapland. The average temperature was between 0.5 and 1 °C above average in most of the country, only Eastern Lapland saw average temperatures close to the long-term averages. The year's lowest temperature, at -41.7 °C, was recorded in Muonio on 5 January, and the highest, at 27.6 °C, was recorded in Utsjoki on 28 July. The last time a highest summer temperature lower than this was recorded was in 1976.
In the country's southern and eastern parts, the year saw higher than average precipitation, with particularly high levels in parts of the south. Initial figures put the year's highest precipitation level at 944.7 mm, recorded in Nuuksio, Espoo, and the lowest at 435.1 mm, recorded in the observation station at Pello Kirkonkylä.
Weather statistics from the Climate Service tel. +358 (0)600 1 0601 (€4.01/min + local charges)
Weather forecasts from the meteorologist on duty 24/7 tel. +358 (0)600 1 0600 (3,85 e/min + pvm)
Weather statistics for December: http://ilmatieteenlaitos.fi/joulukuu (in Finnish)
Annual statistics: http://ilmatieteenlaitos.fi/vuositilastot (in Finnish)
Meteorologists tweet about the weather on Twitter: @meteorologit