Today we are taking a quick look back at Edmonton's weather for December, 2020. This will be a little bit shorter than the typical months-in-review because a lot of things will be covered in the 2020 Year-in-Review Spectacular instead.
High Temperatures
December 2020 started warm, cooled-off for a week in the middle, warmed-up again for a week around Christmas, and then finished things a little bit above average. We didn't set any new records, although the start of the month was right up at the top of our 30-year range. For the month as a whole 23 Highs were above the 30-year average and 8 were below.
It always seems surprising, but in December Edmonton averages about 10 days with Highs above freezing (which show up here as the pink squares). Some years are well below that: 2012 had 3, 2009 had 1, and 2010 had 0.
December 2020 had 17 Highs above freezing, and that ties 2017 but is below the 19 in 2011 or the 23 in 1999. 2020 also had 10 Highs which broke 5°C, and December only averages 3 of those. 2020's 10 matches 2011 and 1997 for the most 5°C Highs in recent years. 2020 did not break 10°C though, which happened in 2017, 2014, 1999 & 1997.
The coldest High was -17.9°C on December 13th, and about one third of the time December doesn't have any Highs below -15°C.
Low Temperatures
The Lows looked a lot like the Highs, with a warm start, slightly cool middle, warm Christmas, and slightly above-average ending. 24 Lows were above the 30-year and 7 were below.
The first -20°C Low of the winter of 2020-2021 was on December 18th at -20.5°C. On average December has 4~5 below -20°C but this year it was just the one.
December Through History
December 2020 ended up as a warm December. The average High of 0.4°C ranks as the 11th warmest since 1880, with the average Low of -8.9°C as the 14th warmest. In recent years Decembers 1999, 1997 and 2011 were all warmer, ranking #1-3 respectively for Highs.
December 2020's Mean temperatures (the average of the Highs & Lows) was 6°C warmer than the 20th Century average for December. That makes it the most above-average month of 2020, with February as the next highest at 4.3°C above average.
December being 6°C above-average is pretty unusual, because since 2000 only the 13 months have been that far above average. 6 of those were Januarys (including January 2001 at 10.8°C above average), 2 were Februarys, 3 were Marches, and December 2011 also came in at 7.3°C.
Snowfall
The International Airport recorded 3.4cm of snow in December 2020, which puts it in the bottom-5 leasts snowy Decembers for the airport.
Snowdepth
We had a few really warm days in December 2020, and the snowdepth at the International fell from 28cm down to around 17cm. Blatchford's numbers did not see as signifiant a drop, spending most of the month in the 15-17cm range. The average snowdepth for the end of December is about 14cm, so 2020 had been High for November-December, but the average has finally caught up with what is currently on the ground.
January Temperatures
In January on-average we get 12 days with Highs above freezing. Since 2000 there have been some low years like 2005 with only 5, but there are other years that have lots of "warm" days like 2001 with 25, 2012 with 17 and 2014 with 16. Recently 2020 had 13, 2019 had 14, and 2018 only had 10.
