The forecast high for the day is 32 C, which would break the previous record for Sept. 5 of 31.7 C, which was set in 1945.
But with the humidity that’s been blanketing the city in recent days, the temperature will feel more like somewhere in the low 40s.
“It looks like it’s going to be a very hot and humid day, not just across the GTA, but across much of southern Ontario,” Mark Schuster, senior meteorologist with Environment Canada, told CBC Toronto early Wednesday morning.
A heat warning is in effect for an area stretching from Windsor in the west to Hamilton in the east, but as of about 7 a.m. it did not extend to the GTA.
Schuster attributed the day’s heat and humidity to “a strong southwest flow of warm and humid air” from the United States.
While today will be “a very uncomfortable day,” Schuster said, particularly for people living without air conditioning, the heat is expected to be “short-lived.”
A cold front will move in Wednesday night and bring with it temperatures that are unseasonably low.
Thursday and Friday should see temperatures in the low-to-mid 20s, but Saturday’s forecast high is 18 C, while Sunday’s is 15 C.
That trend should last for about seven days, Schuster said, “but there is an indication that, as you look out ahead toward the middle of the month, it does look like temperatures may start to go above normal once again.”