December 2014 Review - Jyväskylä

The final month of 2014 recorded above average temperatures not only in Jyväskylä, but throughout Finland. The western parts of Northern Ostrobothnia, south of Oulu and out to the coastal town of Raahe, were especially mild. Locations there recorded an average temperature more than 4.0C above the long term figure. Most of the country saw above average precipitation also, although snow depths were below average in the south.

In Jyväskylä the difference above the long term average wasn't quite as high. The average minimums and maximums for Decembers since 2008 are shown below.

December averages at Jyväskylä Airport for the period 2008-2014

As the graph shows, and as I have mentioned previously, recent Decembers at Jyväskylä Airport have fluctuated quite a lot in recent years. 2008, 2011 and 2013 rank as the warmer Decembers, while 2009, 2010 and 2012 can be classed as cold ones. 2014 was colder than the three warmer Decembers, but nowhere as cold as the others. The Finnish Meteorological Institute recorded an overall average for Jyväskylä Airport of -3.0C, compared to my -3.5C. The 1981-2010 average is -6.2C.

As with the averages, three of the four extremes for the month were in the middle of figures since 2008. In all three cases, the three higher figures were from 2008, 2011 and 2012. The lower figures were from 2009, 2010 and 2012.

The highest overall temperature for the month of 4.3C came on the 4th. The coldest temperature overall was seen on December 28. The -24.5C reading was the third coldest minimum of the year. Christmas Eve a few days earlier had seen the coldest maximum of the month when it only got as high as -12.5C. This was the eighth coldest day of the year. The highest minimum was seen on December 8. It wasn't lower than 1.5C then, and this was the second highest such figure in the seven Decembers since 2008.

As with quite a few other months in 2014, December in Jyväskylä can be divided into two main parts. The first three weeks of the month saw very mild conditions. Up until December 21, there had been only two minimums below -5C. There was also a run of 12 days with a maximum above zero, equalling 2011's longest run. December 2013 saw 17 straight days go above zero. 2010, on the other hand, didn't see one recording above zero.

A cold change eventually arrived in Finland late on December 21. Temperatures dipped sharply, going below -20C in Jyväskylä by Christmas Day. Not since January 31 earlier in the year had it been that cold. December 22 to 30 had an average minimum of -15.8C, almost 10C below the overall monthly figure. A climb back above zero late on the 30th, however, gave some respite from the cold.

The graph below showing the daily minimums and maximums further highlights the change that occurred.

Daily minimums and maximums against rainfall at Jyväskylä Airport for December 2014

Precipitation can also be seen in the graph above. Based on my recordings, Tikkakoski saw a total of 53.3mm fall throughout the month. FMI listed their measurement at 55mm. Both are above the 1981-2010 average of 47mm. December 2013 saw a monthly total of 69mm, although most of that was rain. Last month, however, saw a decent amount of snow, especially from the middle part of the month onwards. Depths were slightly below the average, but they did exceed the highest depth seen during last winter, getting to almost 20cm.

There were 22 days of precipitation. This included the longest consecutive run of precipitation days for 2014. The 17 days between December 5 and 21 all saw falls. The warm change that arrived on December 30 brought snow and later wet snow. This led to the highest daily total of the month with 8.6mm. Only three days recorded a total above 5mm. The longest dry streak of five was experienced when colder temperatures arrived on the 22nd.