Cooldown hits southern Ontario, but we could squeeze out another 20-degree day
A noticeable temperature drop will bring southern Ontario's 20-degree days to an end for now, but we could see it at least one more time this weekend before fall settles in for good
Southern Ontario isn't ready to give up the keys to winter just yet, but it will have to soon.
On Tuesday, Toronto's Pearson International Airport hit a balmy 21.3°C, a nice bonus for mid-October — before a fast drop midweek and another warm-up over the weekend. Wednesday will see the 20s come to an end with the cooler air moving in. Toronto has a forecast high of 13°C on Wednesday.
Historically, that is when T-shirt weather typically ends. Over the last decade, Toronto's final 20°C day has averaged on or around Oct. 22, with the most recent record set on Nov. 10, 2020.
Ottawa follows a similar seasonal pattern, with its latest 20°C temperature falling between Oct. 10 and Nov. 11.
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Few misses, quick flips
While most Octobers provide at least one warm encore, a handful have completely missed the mark entirely.
According to Toronto's weather records, the only years when the city never surpassed 20°C were 1977, 1981 and 2009.
The earliest "final" warm day occurred on Sept. 17, 1977, when the temperature reached 23.5°C—and that was it.
Even a mild fall can change quickly. Fall 2020 was one of the warmest in recent memory, but snow fell quickly weeks later: Ottawa received 10.4 cm on Nov. 25, Toronto received 19.4 cm by Nov. 22 and Windsor received 8 cm on Nov. 30.
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When warmth overstays its welcome
In December, temperatures can reach 20°C, which is unusual but not impossible.
Historical outliers include Dec. 31, 1875 in Windsor (20.0°C), Dec. 14, 2015 in Welland (20.1°C) and a pair of readings on Dec. 3, 1982, when both Toronto (20.0°C) and Hamilton (21.2°C) made it feel like fall would never end.
However, this year's warmth is unlikely to last very long. With milder-than-normal weather expected to last until late October, a few more 20°C days are inevitable before a pair of cold fronts eventually close the door until spring.
So, grab your light jacket while you can as Ontario's extra stretch of warmth will not last forever.