2020-2021 Winter In Review: Temperatures

Spring is here, at least according to the calendar. That means that it is time to take a look back at the winter of 2020-2021. However, in Edmonton "winter" definitely does not begin on December 21, and so we will be looking at is the period from November 1st through March 20th. 

Daily High Temperatures

The thin grey line in this chart is the 30-year average High, and November makes a nice start to "winter" because the temperatures in early November mirror late-March. At the start of November our average High is around 4°C, that falls to -8°C by the time winter officially starts in late-December, and then by late-March it's back around 4°C.

For the winter of 2020-2021 then:

• November when from a really warm start, to just below-average for two weeks, to back above average.
• December was well above-average, except for a few cool days from the 11th through 17th.
• January was also well above-average, until temperatures dropped on January 23rd.
• February started below-average, but then dropped into the coldest-in-30-years range from the 6th through 14th. It bounced back up starting on the 19th, though.
• Early March was mostly well above-averarge, with the 10th dipping just below average.

In total we had 88 Highs above-average, including 7 which were the warmest-in-30-years. And that compares to 52 below-average days, including 6 that were the coldest-in-30 years (and were all from February 8-14).

"Warm" Winter Days

From November 1st through March 20th is 140 days, and during that time we had 73 days with Highs which hit 0°C, or 52% of the time. That's above the average of about 64 days, and it is the most since the winter of 2015-2016 which had 81.

Included in that were 40 days which hit 5°C, or 28% of the winter. The average is about 30 days, and this was the most since 2004-2005 which had 42.

This winter did have the distinction of going 29 days in-a-row without a High that hit 0°C, and that was from January 21st through February 18th. The record was 82 days from November 11th 1955 through February 1st 1966, and compared to that our 29 days is not very impressive. But 29 days was the longest since 2011 with 38 days, and it was about a week longer than the typical 21 days that we get each winter.

Daily Low Temperatures

Here are the Low Temperatures for the winter, and they look similar to the Highs with the big coldsnap of late-January through mid-February really standing out, while everything else was quite mild.

We had 85 above-average Lows. That included 7 which were the warmest Lows in 30 years, and March 14th set a record warmest Low at 3.9°C. In comparison there were 55 below-average Lows, including 2 coldest-in-30-years Lows on February 8th at -31.6°C and February 11th at -28.9°C.

Cold Winter Days

Looking at the very coldest days this winter we had 22 Lows hit -20°C, compared to an average of about 25 each winter. The first one was on December 18th, and then the other 21 were all crammed into roughly a month from January 23rd through February 17th.

Included in that were 8 Lows at -25°C, all from February 6th through February 14th. We average about 11 of those each winter. 3 Lows hit -30°C, all in a row on February 7th through 9th. And February 7th was the coldest Low of the year at -33.9°C.

The Horserace

In this chart the red line shows how the temperatures each day compared to the average temperature for the 20th century. When days were above-average days the line goes up, and for below-average days it drops. 

For the start of the winter in November things were fairly flat, but starting in December the lines really started to climb through late-January. The deepfreeze in late-January and February pushed things down for a few weeks, and then they recovered again with the warm March.

As of March 20th this was the 17th warmest November 1st through March 20th, with the Lows as the 16th warmest and the Highs in the 18th spot. During this winter we averaged about 3.2°C warmer than the 20th century average.

If you change the timeframe for this chart to December 1st through March 20th this was the 13th warmest winter, at about 4°C above the 20th century average.

Across Canada

Here we have the relative temperatures for November 1st through March 20th, compared to the 20th century average, for 9 cities across Canada. There are based on the mean daily temperatures (the average of the High and Low), but the High or Low can be selected from the dropdown on the lower left.

As we saw, for Edmonton this was the 17th warmest November 1st through March 20th, and Calgary and Regina were in roughly the same spot. Toronto and Vancouver were both down around #25. For Ottawa and Montréal it was the 10th warmest, for St. John's it was #8, and for Winnipeg it was way up at #7.

Warm and Cold Months

Breaking things down by month the cold February (shown here as the big, blue bubbles) wasn't just in Edmonton, but stretched from Vancouver through Toronto. On the other hand the prairies had a very warm March, while in central Canada it was fairly average.

For November through March for these 9 cities the only below-average months were February for Vancouver through Toronto, and March was just a tiny bit below-average for Ottawa and Montréal. Everything else was in the orange, and generally well above-average.

Warm Winter Days Across Canada

This chart shows the number of "mild" days with Highs of at least 0°C for each Canadian city from November 1st through March 20th. Unsurprisingly Vancouver blows away the competition, with just about every High above freezing. Toronto is next with an average of about 100 days, and Calgary and St. John's are both around 85. Montréal and Ottawa average around 75, with Edmonton at 65. Regina is down at 50, and finally Winnipeg averages 38.

Taking it one step further to 5°C Vancouver is again at the top, with only about a week or two each winter which doesn't hit 5°C. Calgary and Toronto next, both averaging around 50 Highs that hit 5°C from November 1st through March 20th. Edmonton, Ottawa, Montréal and St. John's all average around 30. And then Regina and Winnipeg are around 15.

Cold Winter Days Across Canada

For -20°C Lows each winter Vancouver doesn't even show up, and St. John's hasn't had one since 1994. Toronto might get anywhere from 0-10, for Montréal it is 3-20, and Ottawa it is 5-40. Average are tough though, because each year is all over the place. The prairies are more predictable though, with Calgary averaging around 20, Edmonton around 24, Regina around 40 and Winnipeg around 50. 

For -25°C Lows each winter it is basically just the prairie cities, with Calgary averaging about 8, Edmonton 9, and Regina and Winnipeg at 24. Ottawa also averages around 6, but that bounces from 0-10 each winter.

That brings us to the end of our look back at the temperatures for the "winter" of 2020-2021. Once the snow at the International hits 0cm we will do a recap of this winter's snow.