Environment Canada has issued an extreme cold weather warning for Toronto, and a large swath of southern Ontario, as frigid temperatures are expected to hit late Thursday night.
The weather agency said a strong cold front is expected to plummet temperatures to -30 C with the wind chill.
A blast of cold Artic air will reach southern Ontario Thursday night and last all day Friday and into early Saturday, Environment Canada said.
Friday is expected to see a high of -13 C with a wind chill of -30 C in the morning and -23 C in the afternoon.
“Cover up. Frostbite can develop within minutes on exposed skin, especially with wind chill,” they warned.
By Saturday, temperatures should begin to ease. Environment Canada forecasts a high of -4 C.
Other areas in Ontario under the same alert stretch from Grey Bruce County, Barrie to Halton and Peel regions, out towards Kingston and Ottawa.
Temperatures in areas such as Ottawa are expected to hit -40 C or -45 C with the wind chill on Friday.
The weather agency has also issued a snow squall watch, saying brief, intense snowfall is expected to develop in Toronto on Thursday evening.
“Under the snow squall, visibilities will be significantly reduced due to the heavy snow,” Environment Canada said.
The weather agency said snowfall accumulations between two and five centimetres an hour are possible, with wind gusts of 50 to 70 km/h.
“Snow squalls cause weather conditions to vary considerably; changes from clear skies to heavy snow within just a few kilometres are common,” the advisory read. “Travel may be hazardous due to sudden changes in the weather.”
-with files from Global News’ Hannah Jackson