Environment Canada issued a slew of extreme cold warnings across the country on Tuesday.
Environment Canada says it issues extreme cold warnings when very cold temperatures or wind chill creates an elevated risk to health such as frost bite and hypothermia.
The agency is asking people to watch for symptoms related to the cold, including shortness of breath, chest pain, muscle pain and weakness, numbness and a change in the colour of the fingers and toes.
Toronto issued an extreme cold weather alert on Dec. 25, with the mercury dipping below -10 C on Monday and falling to -15 C in the early hours of Tuesday morning.
In British Columbia, the agency warned that the Yoho Park and Kootenay Park region could see wind chills as low as -40 C due to a cold arctic ridge of high pressure that it predicts will remain over the region for several days.
Much of Alberta, Manitoba and the entirety of Saskatchewan were also subject to the warnings, and Environment Canada says the frigid temperatures are expected to continue through the end of the week.
Environment Canada issued the warning for parts of northern Ontario too, along with a snow squall warning for Sault Ste. Marie, Ont.
Southern Ontario was largely spared from the extreme cold, save for parts of southwestern Ontario surrounding the Georgian Bay.
In Quebec, the agency warned that the cold arctic air was moving southward on Christmas Day night and Boxing Day, and would continue to do so on Wednesday.
It said wind chills could reach -42 C in the province.
While the Atlantic provinces were largely spared from the extreme cold warnings, much of Newfoundland and Labrador was subject to wind and blizzard warnings, as well as blowing snow advisories.
-- With files from CP24.com