2020 in Review - Part 2 - Temperatures Across Canada

In Part 1 of our 2020 review we took a detailed look at temperatures in Edmonton. In Part 2 we will be expanding that out to 8 other major cities across the country. Part 3 will be about 2020's Precipitation, and Part 4 will be Snow.

2020 Across Canada

In this chart each year since 2000 appears as a bubble. Orange bubbles were warmer than the 20th century average for the city, 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. These are calculated using the Mean temperatures (the average of the daily Highs and Lows), but with the dropdown on the lower right you can switch to look at the Highs or the Lows.

In 2020 all of the cities that we look at were warmer than their 20th century averages, with Edmonton at the cooler end of things:

• Vancouver 0.7°C warmer than the 20th century average
• Edmonton 1°C, Calgary 1.2°C, Regina 1.2°C, Winnipeg 1.1°C
• Toronto 1.1°C, Ottawa 1.4°C, Montréal 1.9°C
• St. John's 0.9°C

Something to notice here is that almost all of the bubbles in this chart are orange. This covers 21 years and 9 cities, and so there are a total of 189 bubbles here, and only 24 of them are blue. Since 2000 Winnipeg & Regina have each recorded 6 below-average years, Ottawa & St. John's have had 3, Toronto & Calgary 2, Montréal & Vancouver 1, and Edmonton none.

That is quite a change from how things used to be:

This chart has the yearly temperature bubbles for 20-year time periods, from 1880-1899 through 2000-2020.

2000-2020's 21 years had 24 blue bubbles across the country. 1980-1999 had 52, and 1960-1979 had 100. Way back in 1880-1899 there were 114 below-average years versus 29 above-average (some of the cities are missing data for those years, so the total number of bubbles is lower).

There have always been some years which were warm and others which were cold, but in the past 20~40 years the cold years have mostly disappeared for Canada's cities.

1841+

Here are all of the years of records together in context. 2020 was not a particularly warm year in Edmonton, with temperatures "only" 1°C warmer than the 20th century average. 

Vancouver was below that at 0.7°C, however Vancouver has a much more moderate (or less extreme) climate than Edmonton because of the ocean. So 0.7°C warmer than the 20th Century average in Vancouver ranks as #26 warmest, while 1°C warmer in Edmonton is #28.

So across the country 2020 ranged from #28 warmest in Edmonton, all the way up to #5 warmest for Montréal. So for all of the cities here 2020 was at least a top-30 year, and for Ottawa, St. John's, Toronto and Calgary it was a top-20.

The last time that all 9 of these cities had a top-30 year together was 2016, which was very warm: #3 warmest for Edmonton, Calgary & Regina, #4 for Winnipeg, #7 for Vancouver, #9 for Montréal...

Canadian Climate Stripes

This is another way of looking at that history all in one place, with the climate stripes for all of the cities. The prairie cities have been mostly in the reds since about 1980, while for the rest of the country it happened a little later around 2000.

2020 in Montréal

2020 was a top-5 warmest year in Montréal, and so we are going to take a closer look at what that means and where the number comes from.

This chart 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 and Lows gives us the Mean, and the overall ranking of...

In Edmonton most of our warming comes from the Low temperatures. In 2020 Edmonton's Mean temperatures was 1°C warmer than the 20th Century average, but that comes from the Lows which were 1.42°C warmer and the Highs which were only 0.49°C warmer. And that pattern is typical, going back years.

Montréal is the opposite, with more of its warming coming from the Highs. In 2020 the Highs were 2.08°C above the 20th century average, while the Lows were only 1.79°C, which gives the 1.9°C total. And warming Highs are pretty typical for Montréal, happening in 2020, 2019, 2018, 2016, 2015...with 2017 as a rare year where the Lows had warmed more than the Highs.

Getting back to 2020, if we follow the red line along we can see that it climbs from January through April, and then takes a little bit of a dip. It then climbs again through September, and takes another little dip. And then it climbs through the end of the year.

Montréal's 2020 Highs

Here are what Montréal's daily High temperatures actually looked like. (just a note that the average line in this chart is the 30-year average, while the other charts today use that 20th century average as their baseline. Sorry about any confusion. This chart is more about the current picture rather than long-term trends)

This chart is a little cramped in this format, but in January-April we see a lot of red, with the temperatures only rarely dipping below 30-year average into the blues. April & May were cold, but then in late-May through July there were a bunch of new records. August, September & October all had a mix of above & below average days. And then there were a few more new records in November and December.

Montréal finished 2020 with 215 Highs above the 30-year average, and 151 below. That included 8 new records for warmest-High, and 1 for coldest-High. So even in a top-10 warmest year there are going to be some cold days.

Warm & Cold Months Across Canada

Here we have the monthly bubbles for all of the cities. Sticking with Montréal we see that January-March were warm, April-May were cool~ish, June-August were warm, September & October were cool, and November & December were warm.

On a month-by-month basis:

• January was above-average across the country, but it was least-above average in Edmonton & Calgary.
• Things flipped for February, with Edmonton, Calgary and Regina well above average, while the rest of the country was just a bit above average.
• Edmonton & Calgary got an extra-cool March, while on the coasts Vancouver and St. John's were a little cool, and the rest of warm.
• April was cool from coast-to-coast, and especially in Edmonton & Regina.
• May was pretty middling, with Vancouver a little warm and Toronto a little cold.
• June was pretty warm from Winnipeg through St. John's.
• July was really warm in Ontario & Quebec, meh in the west, and cold in St. John's.
• In August things flipped, with Edmonton, Calgary & St. John's the most above average.
• That continued into September, with Edmonton, Calgary, St. John's & Vancouver warm, and Winnipeg through Montréal cool.
• October was really cold on the prairies, meh in central Canada, and warm in St. John.s
• November was pretty warm everywhere except Edmonton.
• And finally, December was warm across the country, and especially across the prairies.

With all of that, that is how each of these Canadian cities ended up with a 2020 that was warmer than their 20th century average temperatures. 

And that brings us to the end of Part 2 of our look back at 2020. In Part 1 we looked at Edmonton's Temperatures. Part 3 will be about Precipitation, and Part 4 will be Snow.