Toronto residents are being warned to cover up all exposed skin, with the temperature just one degree away from tying this year's record low.

The temperature dipped to -23 C early Friday morning, but Environment Canada estimated that it felt more like -31 with the wind chill. The morning wind chill was only one degree away from the coldest recorded in 2015, exactly one month ago. On Jan. 13, temperatures were recorded at -24, and it felt like -32 C.

The mercury is expected to rise to -9 by 9 p.m. on Friday, according to the weather agency, but will feel like -17 with the wind.

It's expected to be -12 on Saturday, and Environment Canada forecasts a low of -22 on Sunday and Monday.

The extreme cold was brought into the city by a cold front hovering over most of southern Ontario. With the wind chill coming from the front, it will feel much colder, but Environment Canada has not predicted exactly how cold it will seem.

The average temperatures for this time of year are between -1 and -8 C.

As a result of the cold, the City of Toronto's Medical Officer of Health issued an extreme cold weather alert on Thursday, which remains in effect until further notice. Friday marks the city's 20th extreme cold weather alert of the year.

Environment Canada also issued an extreme cold warning on Thursday, but the warning was dropped on Friday shortly before 10 a.m.

While anyone who isn't dressed warming is at risk in cold weather conditions, the City of Toronto warns that some are at a greater risk for frost bite and hypothermia.

Residents of the affected areas are asked to check up on vulnerable loved ones including the homeless, outdoor workers, elderly, infants and people with medical conditions.

Environment Canada has issued warnings for the following areas:

  • Algonquin
  • Bancroft-Bon Echo Park
  • Brockville-Leeds and Grenville
  • Burk's Falls-Bayfield Inlet
  • Cornwall-Morrisburg
  • Haliburton
  • Parry Sound-Muskoka

The following areas are no longer Environment Canada's warning:

  • Barrie-Orillia-Midland
  • Belleville-Quinte-Northumberland
  • Dufferin-Innisfil
  • Dunnville-Caledonia-Hamdliand
  • Grey-Bruce
  • Halton-Peel
  • Hamilton
  • Huron-Perth
  • Kingston-Prince Edward
  • Niagara
  • Ottawa
  • Oxford-Brant
  • Peterborough-Kawartha Lakes
  • Prescott and Russell
  • Renfrew-Pembroke-Barry's Bay
  • Simcoe-Delhi-Norfolk
  • Smiths Falls-Lanark-Sharbot Lake
  • Stirling-Tweed-South Frontenac
  • Toronto
  • Waterloo-Wellington
  • York-Durham