I have a confession to make – I’m a weather nerd. Thanks to Environment Canada’s historical climate data page, I now have downloaded complete weather data for Toronto since 1919, which I can view in a spreadsheet, query in a MySQL database, or bore any or all of my friends (and blog readers) with. What fun!
As I write this, Toronto has just emerged from its second extreme cold weather alert of the winter. According to the City of Toronto’s Housing and Homelessness page, Toronto had had eight cold weather alerts by this time last year. The city went on to have 16 alert days in January and 12 in February that year, so perhaps we shouldn’t complain too much. (Not that that’s going to stop me.)
As a contrast, I looked in my weather database to see what the hottest days in Toronto history have been. It turns out that there have been exactly three days on which the temperature went over 40 degrees Celsius, and they were consecutive: on July 8, 9, and 10, 1936, the temperature reached 40.6C. It remained hot for several more days after that, with the temperature gradually diminishing.
It turns out that the 1936 heat wave was legendary in North America, and that Toronto got off relatively easily. According to the Wikipedia article on the subject, Chicago had 12 consecutive days above 100F, Steele, North Dakota, reached 121F (49C) at one point, and the heat continued into August in some American states. All of this was before homes and businesses were commonly air conditioned, which forced people to flee to movie theatres, beaches, parks, and anywhere where even a hint of a breeze was possible. According to Heritage Toronto, 225 people were killed in the city during the heat wave – the largest spike in deaths since the 1918 flu – and many people drowned trying to escape it.
Oddly enough, the city didn’t have that many more hot days than usual that summer. According to my handy MySQL database, the city had 47 days above 27C in 1936, which is above average but not unusually so. By way of comparison, 2010 had 59 days, 2007 had 65, and 2002 had 72; the record is 1959, which had 79 days above 27C. At the other extreme, the summer of 1992 had only 10 hot days, thanks to the Mount Pinatubo eruption. The city got over 30C only twice that year – June 13th and August 26th. I’m pretty sure that people living through the 1936 heat wave would happily have traded places with 1992.