May was chilly, dry, and without thunder

According to Finnish Meteorological Institute statistics, May was 1-3 degrees colder than usual in the whole country. The month was exceptionally chilly especially in Northern Ostrobothnia and Kainuu; something which happens on average a couple of times in a century.

The highest temperature of the month was measured 19 May, which was also the only hot day of the month. On this day, the temperature rose to 27.0 degrees in Evo, Hämeenlinna. The month's lowest temperature, -13.1 degrees, was recorded in Pesiö, Suomussalmi, on 16 May. 

Unusually dry in most parts of the country

In Lapland, the precipitation in May was between 10 and 20 mm, which is exceptionally or unusually low. Similarly low levels are seen on average once every 10 to 30 years. The lowest amount of precipitation, 5.6 mm, was measured at an observation station in Angeli, Inari.

The usual amount of rainfall, circa 40 mm, was reached only in Northern Ostrobothnia and Kainuu. The highest amount of precipitation, 60.4 mm, was measured in Kalliojoki, Kuhmo.

In the southern part of the country, May was very dry for a long time, and forest fire warning was in effect for nearly the whole month. However, the precipitation on the final days of the month changed the monthly statistics so that they are closer to the long-term average.

There were only 239 observed cloud-to-ground lightning strikes in Finland, which is the third smallest number in the past 60 years or so.

The spring was slightly colder than usually

Considering the spring months, March was warmer than usually, while April and May colder than average. The spring was colder than usually in the northern parts of the country, where the temperature deviation varied between 0.5 and 1 degrees. However, in the south the spring was quite usual in terms of the average temperature.

The spring's precipitation was higher than usual in the Ostrobothnian provinces and in Kainuu. Elsewhere in Finland, precipitation levels were even unusually low, which means they are seen on average once every 10 years.

Further information:

May weather statistics: http://ilmatieteenlaitos.fi/toukokuu