Today we are taking a look back to see how Edmonton's 2020 temperatures compared to other years. In Part 2 we will expand that to cities across Canada. Part 3 will be about 2020's Precipitation, and we will close things out in Part 4 with a look at snow.
Warmest & Coldest Years
We'll get the big news out of the way: Edmonton's average temperature for 2020 was the 28th warmest overall, at 1°C warmer than the 20th Century average. That's warmer than 2019 (#56) and 2018 (#36), but below 2017 (#15), 2016 (#3) and 2015 (#4)
9 months were warmer than their 20th Century averages, including December at 6°C warmer than average and February at 4.3°C. The 3 cooler months were March, April & October, with October -2.5°C cooler than its average.
For the Climate Stripes chart that makes 2020 a light pink. It is darker than 2019 at 0.4°C, but much lighter than 2016 at 2.9°C
The last time that we had a blue stripe was back in 1996, at -1.7°C colder than the 20th century average.
The Horserace
This chart shows where the "28th warmest year" calculation comes from.
It tracks how much warmer or colder each day of 2020 was compared to the 20th century average. Warm days get points and push the red line upward, and cold days drop the line down. It is split into Highs, and Lows because the Lows tend to have warmed up more than the Highs have. And then the average of Highs & Lows gives us the Mean.
Following the line for the Highs:
- in January it climbed and then dropped
- it climbed in February and into March
- it dropped in late-March and into April
- it was basically flat for May all the way through September
- in October it climbed a bit, and then dropped a bit again
- it climbed through most of December.
The Lows look pretty similar, except that they slowly a bit during the summer.
So at the end of the year the Highs ended up at 0.49°C warmer than the 20th Century average, for our 49th warmest Highs. And meanwhile the Lows were 1.42°C warmer for 24th warmest Lows. The average of the two gives us 2020's total of 0.96°C above the 20th century average, and 28th spot.
Warm & Cold Months
In this chart each month since 2000 appears as a bubble. Orange bubbles were warmer than the 20th century average, and blue bubbles were colder. The size of the bubble represents how warm or cold it was, and if you hover over them you will get a bit more information. Here we are back to using the Mean temperatures, but with the dropdown on the lower right you can switch to look at the Highs or the Lows.
- January was warmer than the 20th century average, but most recent Januarys have been "warm." 2020 was actually the coldest January that we had had since 2004.
- February was fairly warm, and was very different from the giant blue bubble for the very cold February of 2019.
- March & April were both below average. But a cold March & April together happens fairly frequently: 2018, 2017, 2014, 2013, 2011...
- May through September were all warmer than the 20th century average, but not by much. And if you switch this chart to show the Highs, May through July were all basically right on the 20th century average, so it was the Lows which made up the difference.
- October was quite cold, and the last time that we had a "warm" October was 2015.
- November was right on the 20th century average.
- December was quite warm, although not quite as warm as 2011.
High Temperatures
This chart is a little cramped, but it has the daily High temperature rollercoaster for the whole year. During the year our temperatures don't spend much time right around the average, and instead bounce back and forth between warm days and cold days.
In particular here we can see the coldsnaps that we had in mid-January, early-April and late-October with the temperatures right down at the bottom of the 30-year range. Overall there were 197 days above the 30-year average and 168 below.
For "warm" days 2020 ended up with 100 days which hit 20°C. That was up from the 82 we had in 2019, but down just a bit from warm years like 2015-2018.
For warmer days, 2020 had 23 Highs which hit 25°C, and that's down from the average of about 40. And 2020 had 2 days hit 30°C, when we average around 6 or 7.
Low Temperatures
And here are the daily Low temperatures for 2020.
The coldsnaps in January, February, March, April and October all stand out. And those included two notable days:
- On January 15, 2020 we hit -37.6°C. That was the first time that Blatchford had broken -35°C since December 13, 2009, and the first -37°C since January 19, 1996. The last time that Blatchford hit -38°C was also the last time that it hit -40°C, back in January 1972.
- On April 2nd the Low was -20.8°C. That was the first time we had hit -20°C in April since April 3, 1982.
Looking at the cold days, 2020 had 19 days with Lows which hit -20°C, which is close to the average. That included 9 Lows which hit -25°C, which is also right on the average. And each year we average about 2 Lows at -30°C, and 2020 recorded 4 including the ridiculous -37.6°C.
Frost-Free Days
Edmonton's final frost of the spring of 2020 was quite early, on April 19th. The average is around May 6th. The first frost of fall was also a little late on October 9th, compared to an average of around September 25th.
The early final spring frost and late first fall frost meant that 2020 had 173 frost-free days, which is about a month longer than the average of 142. In recent years 2011 had 174 frost-free days, and 1980 was the longest with 185.
Edmonton versus Calgary
And finally, just for fun here is a comparison of the daily temperatures in Edmonton & Calgary for 2020. Generally the two cities move together, although sometimes some big gaps open up.
The largest difference was on January 19th with Edmonton's High at -16.5°C, while Calgary was 21.4°C warmer at 4.9°C. That was that was the start of a warming trend that reached Calgary first, and Edmonton was above freezing by the 21st. The largest difference in Lows was in that same gap on January 20th with Edmonton at -17.6°C and Calgary 13.5°C warmer at -4.1°C.
In the charts there's a thin line (it's a little tough to see) which shows the average difference each week. During the winter Calgary's Highs average about 4~5°C warmer than Edmonton's, while the Lows are a little bit closer at 2~3°C warmer. In the summer Edmonton's Lows are usually 1~2°C warmer that Calgary's, while the Highs are a bit of a mix.
With that we have reached the end of Part 1 of our review of 2020. In Part 2 we will look at temperatures in some of the major cities across Canada. Part 3 will be about a Precipitation. And we will end things off in Part 4 with a look at snow.
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