The last time that the Blatchford weather station recorded a temperature of -30°C or lower was back on January 4, 2015 with a Low of -30.2°C. As I write this on December 28th we've gone 1,088 days without a -30°C, but that streak might be ending because we have a few cold really night in the forecast. 1,088 without a -30°C sounds impressive, but is it?
Really Cold Days
This chart shows every day since 1880 that had a recorded Low temperature of -30°C or below. The dots are colour-coded so that the colder days have darker dots, although it's a little hard to tell them apart here, but we'll take a closer look at that later on.
There are a few things to take from this chart, but the best place to start is to compare the left and the right sides. The left side of the chart - especially the 1880s - is much more dense because there were many more cold days recorded. And in recent years - from about 1980 onwards - temperatures below -30°C have been fairly rare. Of the last 20 winters there were 9 that didn't have any -30°C temperatures.
Another thing to notice is exactly when those -30°C temperatures show up. Since 1997-1998 we've had 7 -30°C days in December, 16 in January, only 1 in February, and 4 in March. The years that had -30°C in March were 2003, 2009 and 2011, and those type of temperatures that late in the year just aren't fair.
This is an old chart that we first looked at way back in one of this blog's earliest posts, and it provides some context for the difference between the left and right side of the first chart. 130ish years ago Edmonton would average 24 days below -30°C each winter, but now that number has fallen to around 1.
Trivia
This chart digs a bit more into the various levels of extreme cold.
- -45°C is ridiculously cold, and even a century ago it was pretty rare. We haven't had a -45°C since February 8, 1939, and there were only ever 17 recorded from 1880-1939. The coldest temperature ever recorded was -49.4°C on January 19 & 21, 1886; and then again on February 3, 1893.
The International Airport still occasionally sees temperatures in that range, including -46.1°C on December 13th, 2009. - The city hasn't recorded a -40°C since January 25, 1972, and before that the previous -40°C was 22 years earlier, on January 26, 1950.
- Currently we haven't hit -35°C since December 13, 2009. That's more than 2930 days, which is the longest we've ever gone without a -35°C. The previous record was 2,556 days from January 27, 1997 through January 26, 2004. And before that the longest record had been 1,856 days from December 25, 1983 through January 31, 1989.
- Our current streak of 1,080ish days without a -30°C is the 4th longest. It's about a month shorter than a 1,109 day streak that ended in 2009, and two months shorter than a 1,138 day streak that ended in 1987. But it's still well below the 1,835 day streak that lasted almost 5 years from January 13, 1998 through January 3, 2003.
Cold Highs
For a change of pace, here are the coldest High temperatures recorded since 1880:
- Edmonton has never recorded a High below -45°C, and there was only ever one at -40°C or lower, right at -40°C on January 30, 1893.
- Highs at or below -35°C were also pretty uncommon, with only 13 of them ever recorded. The most recent was a -35°C on January 20, 1943.
- Edmonton has had 110 days with Highs of -30°C or below, although since 1980 there have only been 6, and only 1 since 2000. The most recent was a High of -30.6°C on January 27, 2004.
- Since 2000 we've had 10 days with Highs of -25°C or below. Most of them have come in groups: January 26-28, 2004; January 28 & 29, 2008; and December 13 & 14, 2009. The most recent was December 6, 2013 with a High of -25°C
- Lows at or below -20°C are fairly common. Recently both 2001 & 2016 didn't have any, but some years had lots: 2008 had 10, 2009 had 10, 2011 had 12, etc.
Lows Below -20°C
And finally, here we're back to Low temperatures, but this time the Lows below -20°C and -25°C have been added. This is a bit of a companion piece to First -20°C of the Winter and the First -25°C of the Winter, since it shows the "season" of cold temperatures in Edmonton.
The -20°C days start around mid-November, and that hasn't changed much over the years. The cold days end by about mid-March, and that's maybe a week or two earlier than they used to. But the big difference here is again the density, with the left side having a lot more dots, and a lot more of the extra-cold dots compared to what we've seen recently.
Today has had a bit of a high-level, historical perspective. If you're interested in the specifics of some recent coldsnaps we looked at those in more detail here: Coldsnaps & Deepfreezes
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