Environment Canada has issued a frost advisory for parts of the Greater Toronto Area, Niagara Region and Chatham-Kent.
In the GTA, the advisory covers Toronto, Mississauga, Brampton, Burlington and Oakville.
The weather agency said plants could be damaged with frost possible Saturday night and early Sunday as the temperature drops to near 0 C.
Global News weather specialist Carla Bosacki said this is the first frost advisory of the season for these regions.
“We’ll see clearing skies and winds coming in from the north and when you have those two combinations, that makes for no insulation with the cloud cover so things get quite chilly,” she said.
“It’s going to be a cold one overnight tonight, a cold start to your Sunday. This is the first frost warning of the season — the first of many I am expecting.”
Bosacki said the weather will warm up next week, though, likely reaching above-seasonal temperatures.