Toronto will feel its first true taste of fall chill Wednesday night, with temperatures expected to drop to 3°C under clear skies — cold enough for patchy frost to develop in parts of the city and surrounding regions.
The dip follows a dramatic shift in the weather earlier this week. On Tuesday, Toronto experienced its first significant rainfall in weeks, marked by showers and thunderstorms that brought an end to a prolonged stretch of mild, dry conditions. That rain ushered in a cooler air mass, setting the stage for crisp nights and seasonable daytime highs.
The forecast calls for abundant sunshine through the remainder of the week, with daytime highs hovering between 14°C and 18°C — right in line with seasonal norms for early October.
On Wednesday, we can expect a daytime high of 15°C, clear skies, and a low of 3°C overnight, with frost possible. Thursday’s high is forecast at 14°C, with sunny skies, and an overnight low of around 6°C.
“Areas that will see some frost [Wednesday night] are away from Lake Ontario, including Markham, Stouffville, Newmarket, Aurora, Barrie, Keswick, and Innisfil,” says CityNews meteorologist Carl Lam. “Expect to see frost on your lawns and on car windshields [Thursday] morning.”
Temperatures will gradually rise to 18°C and 19°C to cap off the week and kick off the weekend in Toronto, with clear conditions expected throughout.
Looking ahead to the long weekend
Historically, Toronto’s average high for the second week of October sits around 15–16°C, with lows near 7°C. This week’s forecast aligns closely with those averages, though the overnight low of 3°C marks one of the chilliest readings so far this fall.
“If you’re right downtown, the warm waters of Lake Ontario prevent temperatures from dropping too much. Overnight lows will be in the mid-to-upper single digits around the downtown core,” Lam adds. “You’ll definitely want a sweater or jacket on Thursday morning since it will be the coldest start for many so far this fall season.”
The fall weather pattern mirrors what the city experienced in October 2024: a rainy start to the month followed by several days of clear, cool sunshine leading into Thanksgiving.
With no rain in the forecast through the long weekend, Torontonians can expect ideal conditions for outdoor gatherings, fall hikes, and Thanksgiving celebrations.
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