December 2013 Review - Jyväskylä

December 2013 in Jyväskylä was a strange month in terms of weather. Even though the start of the month was warmer than some previous Decembers, there were some hints of an approaching winter, but it ended with warm weather, rain and questions being asked about when the true Finnish winter would really begin. The table below shows the averages since 2008.

December averages in Jyväskylä for the period 2008-2013

The average maximum of 1.7C was the warmest in the years since 2008, beating 2011's 1.6C. According to the Finnish Meteorological Institute, the overall average temperature for December 2013 in Jyväskylä was more than 5C higher than the 1981-2010 average. The strangest part about the warm weather in December was that it came towards the end of the month. The final 11 days had an average maximum of 4.0C. The same period in 2011 had an average of 1.7C while 2010's figure was -14.6C.

December 2011 held on to the highest average minimum of the 2008-2013 period though, as 2013's -3.3C was over a degree cooler. This is somewhat surprising considering there were a total of 13 days that didn't go below zero in 2013 compared to 7 in 2011 and 5 in 2008. Every December day in 2009, 2010 and 2012 went below zero at some point. However, 2011 had only 1 daily minimum below -10C compared to 5 for 2013.

In terms of extremes for the month, both the highest maximum of 5.9C from December 17 and the highest minimum of 3.4C from December 28 were the highest respective figures in the period since 2008. The lowest temperature of the month of -14.6C, as well as the lowest daily maximum of -6.2C, occurred on December 9. These figures were lower than those in both 2008 and 2011, but were still easily above those in 2009, 2010 and 2012.

Extremes elsewhere in Finland included a monthly high of 8.6C in Maarianhamina in the Åland Islands and a monthly low of -39.7C in Sodankylä in Lapland.

If we look at the past 6 Decembers in Jyväskylä, it is quite easy to divide them in to warm and cold ones. There are the warm Decembers of 2008, 2011 and 2013 and the cold Decembers of 2009, 2010 and 2012. The graph below shows the daily average temperature during each December.

Daily average temperatures in Jyväskylä for December in the period 2008-2013

The graph makes the distinction between the warm and cold Decembers much clearer. The yellow line, which indicates 2013, can also be seen above other years for the last 12 days, further highlighting the unusual warmth that was experienced.

Rainfall for December 2013 was above the 1981-2010 average. A total of 69mm was recorded in Jyväskylä, compared to 56mm last year and the average of 47mm. Snow was around for most of the first half of the month. A depth of 7cm was recorded on December 15, but the warm temperatures in the latter half of the month ensured there was no snow for Christmas or New Year's Eve. Kilpisjärvi in the far north had 117cm on December 4. By the end of the month this had dropped to 106cm.

Warm, humid southwesterly and southerly winds dominated for most of the month, contributing to the warmer temperatures. There were a couple of windy days to note, including December 1 and 13, when the storms Oskari and Seija hit Finland.

In the end it was a disappointing December that, while featuring a few cooler days at the beginning of the month, failed to deliver a white Christmas and New Year. Perhaps winter will arrive in January.