Environment Canada says the "very cold wind chills" will hit be felt in the city on Thursday night and early Friday morning, as an arctic air mass combines with light-to-moderate winds. As a result, an extreme cold weather alert is in effect.
The weather agency says the temperature may hit –22 C overnight.
A parallel extreme cold weather alert is in effect from Toronto Public Health.
The extreme cold weather alerts from public health are typically issued when temperatures are expected to hit –15 C or lower.
People living in Toronto are asked to check in on friends, family and seniors who may be vulnerable. City residents are also asked to call 311 if they spot anyone on the streets who appears in need of help in this weather.
Toronto has seen repeated cold weather alerts issued this winter. And this February has been one of the coldest in decades for Ontarians, according to Environment Canada.