April 2015 Review - Jyväskylä

Finland saw above average monthly temperatures again in April 2015. The differences above the average weren't quite as great as those seen in February and March though. The greatest differences, 2.5C to 3.0C above average, were seen in the far north, but almost the whole southern half of the country, including Jyväskylä, saw a maximum difference up to only 1.5C. Rainfall distribution varied quite a lot across Finland during the month, but Jyväskylä recorded an almost average total.

According to the Finnish Meteorological Institute, the average temperature in Jyväskylä was 3.4C. My figures resulted in an average of 3.7C. This is against last year's 3.7C (3.3C), and the long term figure of 2.2C.

The average minimums and maximums for the past seven Aprils can be seen below.

April averages at Jyväskylä Airport for the period 2009-2015

The average minimum of -0.3C for this year is the highest of the past seven Aprils. The average maximum is also quite high in comparison to recent years, although still 2C and 1.5C lower than the respective years of 2011 and 2014. FMI records show that 14 of the past 17 Aprils in Jyväskylä have been above the 1981-2010 average.

Jyväskylä's extremes for the month ranged from -5.3C on April 6 to 14.9C on the 12th. The -5.3C figure was the second highest such figure in the years since 2009, colder only to the -5.1C seen in 2010. Aprils from 2011 to 2014 all saw a minimum below -10C. A maximum of 14.9C is right in the middle of figures from 2009 onwards. 2013 saw the lowest figure with 12.6C.

Both April 2 and 3 saw the coldest maximum of the month. It only topped 2.0C on each day. This was the equal second highest respective figure, while the highest minimum was the second lowest. April 8 saw a lowest temperature of 3.1C. Only April 2010's figure of 2.8C was lower. 2009, 2011, 2012 and 2014 all saw a figure above 4C.

The national extremes for April were, strangely enough, recorded on the same day. April 12 saw very warm temperatures in the southern half of the country. It reached 17.1C in the Southern Ostrobothnian town of Kauhava. In the Lapland town of Kittilä, however, it dipped to -15.5C.

Minimums during the month remained fairly stable and maximums only climbed slightly, as seen in the graph below. Another observation from April 2015 was the lack of cold nights, but, as mentioned above, warm nights were also uncommon. April 2015 also saw a lower difference between the average minimum and maximum than any other year since 2009.

Daily minimums and maximums against rainfall at Jyväskylä Airport for April 2015

Rainfall was distributed unevenly across the country. The south east saw the highest totals. Some locations there recorded over double the average April rainfall, but southern parts of the Finnish west coast, as well as from just south of Oulu to the far north, saw below average totals.

A total of 13 days of precipitation led to a total of 33.0mm for Jyväskylä. FMI recorded 34mm. Both are very close to the 1981-2010 figure of 35mm. April in 2014 saw only 21mm. April 23 was the wettest day for Jyväskylä. A total of 8.7mm fell at Tikkakoski. The 23rd was one of three days that saw a daily total above 5mm; the 26th and 29th being the other two. There were two three day streaks of rain; April 2 to 4 and 12 to 14. The longest dry streak was seven days from the 5th to 11th.

There was no snow left at Tikkakoski by April 15. The bare winter of 2014 meant there was no snow by the same date as well, but the average depth between 1981 and 2010 at April 15 was 19cm.

A strong low pressure and storm system moved into Finland on April 29. Only 8.0mm was recorded at Jyväskylä, some of which was wet snow, but other locations saw much higher totals. Puolanka, north of Kajaani in the Kainuu region of Finland, had 91cm of snow by the month's end. Some locations in that part of Finland saw up to 20cm of fresh snow as a result of the April 29 storm. FMI reported such high levels of snowfall as very unusual for this time of the year.