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Weather and Climate | Climate in Finland | Normal period 1971-2000
Climatological statistics for the normal period 1971-2000
Helsinki (60� 10`N 24� 56`E) is the Capital of Finland and it is located nearby the southern coastal area. Jyv�skyl� (62� 24`N 25� 40`E ) is in the middle of Finland and Sodankyl� (67� 22`N 26� 37`E) stays in the middle of Lappland, locations: the chart. Sodankyl� is precise under the number 19 in the chart.
The publication "Tilastoja Suomen ilmastosta 1971-2000 - Climatological statistics of Finland 1971-2000" contains information in three different types of tables. The first table type includes monthly average values and extremes for the temperature. It also contains the monthly average values for pressure, precipitation, relative humidity and average of snow depth on the 15th and last day of the month. Numbers of temperature- and precipitation days for all 114 stations are also published. Here are the examples for Helsinki, Jyv�skyl� and Sodankyl�.
The Finnish Meteorological Institute among many other meteorological institutes throughout Europe has published a new climatological 30-year summary concerning the period of 1971-2000. The need of updated climatological 30-year statistics was obvious already in the end on 20th century. However, the former period 1961-1990 will still remain the official normal period defined by WMO. The next official normal period is 1991-2020 but until then we probably see the statistics for the period 1981-2010 as well as we now see for the period 1971-2000.
The comparison of the mean temperatures of January and July for the official and unofficial periods indicate the same as the comparison of winter and summer seasons.
From this table one can see some mean values of January and July for the offical and the unoffical periods.
Temperature is a continuously changing climatological factor. Diurnal variation gains a lot of attention but so do the longer scales' oscillations as well. For instance the 10-year periods are quite an interesting tool for comparing the little bit longer time steps with each other. The next picture represents the 10-year mean temperatures for Helsinki Kaisaniemi, Jyv�skyl� and Sodankyl� during the last hundred of years.
It is obvious from this picture that the 1930's was approximately as warm as the 1990's - actually it was some decimals warmer if only Jyv�skyl� and Sodankyl� are taken into account.
Many of us who live in Finland noticed the remarkably mild winters in the 1990's. As we calculated the statistics one important fact arose above others. The rising of the mean temperature between the periods 1961-1990 and 1971-2000 was about 1 degree Celsius for the four months December, January, February and March. That big a change is statistically significant.
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This picture shows the deviation of the mean temperature of the winter months December-February for the years 1961/62 - 2003/04 as compared to the new 30-year period 1971-2000 in Helsinki Kaisaniemi. The official 1961-1990 value for the mean temperature in Helsinki Kaisaniemi is -4,8 while for the new 30-year period it is only -3,8 degrees Celsius.
As we compare the periods 1961-1990 and 1971-2000 with each other, we can easily find that there are no significant changes in the summer seasons to be seen. Meanwhile the influence of mild winters in the 1990's is quite clear. The mean temperatures for the winter seasons 1971-2000 are almost all over Finland one degree higher than for the offical normal period 1961-1990. But then again if we would choose to compare the normal period 1931-1960 to the period 1971-2000 we would get other kinds of results. However, it is a fact that the climate is warming and some effects can be seen already.
The amounts of precipitation of 1961-90 are very similar to the ones in 1971-2000.
The mean annual temperature and the average annual precipitation for the whole period 1971-2000 are visualized in a nationwide map format. These fields have been produced by using the so called kriging-analysis method. The resolution is not sufficient enough to bring out all the details for our knowledge but does however provide us with suggestive information. The Finnish Meteorological Institute has the possibility to produce more detailed information if customized.
The mean annual temperature (�C) is on the left and the mean annual rain amounts (mm) on the right.
Table type 2 in the publication 1971-2000 includes the wind frequency distribution of all the 37 observation stations. In the example below you will find the wind distribution of Mustasaari Valassaaret situated in the Quark, the narrowest part of Sea of Bothnia.
In table type 3 are the monthly mean as well as the monthly absolute maximum (eniten) and minimum (v�hiten) values of duration of sunshine. In the publication 20 observation stations measuring the solar radiation are taken into account. In the table below is the example for Helsinki Kaisaniemi.
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