Normal period 1981-2010

The Finnish Meteorological Institute among many other meteorological institutes throughout Europe has published a climatological 30-year summary concerning the period of 1981-2010. The need of updated climatological 30-year statistics was obvious already in the end on 20th century. However, the former period 1961-1990 still remains the official normal period defined by WMO.

It is common nowadays that the long term climate statistics are updated every ten years. The new normal period 1981-2010 provides information on the current climatic conditions and is an important foundation when interpreting current weather phenomena.

Mean temperatures have risen

The annual mean temperature of Finland in the 1981-2010 normal period was almost 0,4 degrees higher compared to the previous normal period of 1971-2000 and approximately 0,7 degrees higher than in the official normal period of 1961-1990. The observed temperature rise is in reasonable agreement with the climate models. 

The month of April has warmed up the most when comparing the new normal period to the previous one. June on the other hand is the only month when the monthly mean temperature in most of the country was cooler than in the previous period.

If we compared the new normal period to the official 1961-1990 values, we can see that the temperature rise has been most notable during winter months. In this comparison June is still the only month where slight cooling is observed.

It should be noted that changes in the observation stations themselves, measuring techniques and the WMO guidelines result in the fact that the different normal periods are not fully comparable with each other.

Seasonal and annual mean temperatures in Jokioinen, Siikajoki and Sodankylä for the three different normal periods
  Jokionen Siikajoki Sodankylä
period 6190 7100 8110 6190 7100 8110 6190 7100 8110
spring  2,8 3,2 3,6  1,1 1,4  1,7 -1,9 -1,5 -1,2
summer 14,8 14,9 15,2  13,9 13,9 14,2  12,3 12,4 12,6
autumn 4,5 4,5 4,9 2,6 2,5 3,0 -0,6 -0,8 -0,3
winter -6,6 -5,5 -5,3 -9,5 -8,6 -8,4 -13,9 -13,1 -12,6
year 3,9 4,3 4,6 2,0 2,3 2,6 -1,0 -0,8 -0,4
 

Mean temperature in 10-year periods

The changes in the mean temperatures can also be viewed in 10 year periods. In the figure below, the 10 year mean temperatures are shown for Helsinki and Sodankylä spanning in total approximately 100 years each.

The 10 year mean temperatures in Helsinki are based on the annual mean temperatures since the year 1900. The temperature series in Sodankylä starts in the year 1910.

No big changes in precipitation

The annual variability in precipitation is large in Finland, at least when comparing to temperature. The average annual precipitation in Finland is slightly higher in the new normal period than in the previous normal period.

The monthly average precipitation in May is higher in the new normal period, whereas precipitation in April and September is less.

Seasonal and annual precipitation sums in Jokioinen, Siikajoki and Sodankylä for the three normal periods
  Jokionen Siikajoki Sodankylä
period 6190 7100 8110 6190 7100 8110 6190 7100 8110
spring 91 97 103 88 86 93 84 92 100
summer 210 217 218 181 193 199 184 181 196
autumn 178 177 181 150 144 146 145 137 134
winter 102 115 125 92 100 103 87 99 97
year 581 606 627 511 523 541 500 509 527

 

Annual mean temperature and precipitation 1981-2010

Maps of the annual mean temperature and precipitation in the 1981-2010 normal period have been done by using the so called "kriging" analysis method. The maps give a good overview of the spatial variation of temperature and precipitation in Finland. However the resolution is not accurate enough for a more detailed look at individual locations.

Annual mean temperature (°C) on the left and annual average precipitation sum (mm) on the right during the 1981-2010 normal period.