Warm spell in Toronto could bring a mild Halloween: meteorologist

Unseasonably high temperatures in Toronto and the GTA this week could bring a warmer Halloween than last year, a meteorologist with Environment Canada says. 

The federal agency forecast a high of 25 C on Monday, with temperatures expected above 20 C on both Tuesday and Wednesday.

At this time of year, the normal temperature high is 12 C, said Geoff Coulson, a warning preparedness meteorologist at Environment Canada. 

"We've seen some cooler temperatures on and off this month, but overall, things have been warmer than normal," he said. "This particular stretch we're living through is significantly warmer than normal." 

Coulson said a warm air mass from the American deep south is flowing across southern Ontario, causing higher temperatures. 

Though temperatures this week are unlikely to reach record highs, Coulson said Toronto and the GTA could see a rare four-day stretch of temperatures above 20 C, including the weather on Sunday. 

"This is really not something that happens very often in Toronto, especially for stretches of these temperatures in the second half of October," he said. 

Warm temperatures possible next week as well 

Temperatures are predicted to cool to a high of 12 C on Thursday, due to a cold front from Northern Ontario, Coulson said. But the agency is expecting temperatures to warm up again next week, thanks to another air mass from the American deep south. 

For the last few days of October and possibly the beginning of November, daytime temperatures could reach the high teens or low 20s, he said. 

In October 2023, there was a stretch from Oct. 24 to Oct. 26 of similarly high temperatures, Coulson said. But by Halloween, Toronto only saw a high of 6.6 degrees, which he said is likely to be "noticeably cooler" than what is expected this year. 

This month has also been unusually dry, with Environment Canada recording only 15 millimetres of rainfall so far at Pearson Airport, he said. 

Coulson said it is unclear how much of this warm spell can be attributed to climate change, but he said climatologists are working more consistently on determining how much influence climate change may have on given periods of weather in certain parts of the world.