Extreme cold warnings in place Monday night for parts of Ontario, Quebec and New Brunswick

Environment Canada has extreme cold warnings in place Monday for northern and eastern Ontario, all of southern Quebec and western New Brunswick.

People in southern Ontario could expected some of the coldest air they've experienced in about three winters, said CBC meteorologist Colette Kennedy.

"This cold hasn't been experienced for a while," said Kennedy, noting the brisk winds were the result of an Arctic front from the northwest. "We've had a relatively mild winter in many cases, especially in the East."

With the wind chill, temperatures could feel as cold as –45 C  in northern Ontario and parts of central Quebec, while the temperature in southern Ontario and western New Brunswick is expected to fall to around –35 C, Environment Canada said.

In Ottawa, the wind is expected to aggravate what should already be the city's coldest temperatures of the pandemic, Environment Canada said.

The forecast for the capital city calls for temperatures steadily falling this evening and overnight to between –25 C and –32 C by dawn Tuesday. Wind chill could make that feel like –35 C.

Environment Canada said Toronto is expected to go as low as -18 C tonight. 

Kennedy said the last time it was this cold in southern Ontario was before the pandemic started in 2020. 

She said temperatures this low mean people should cover as much exposed skin as they can, dress in layers — ideally a wind-resistant outer layer — and watch for cold-related health problems such as muscle pain, numb extremities and shortness of breath.

"The strong winds pull any heat your body is providing, away from you," said Kennedy. "So, that's another reason that people just have to be so cautious because it can be a very, very short period of time where you could get into a situation with frostbite or worse."

In Montreal, temperatures are expected to dip to about –26 C overnight and wind chill values could feel as low as –38 C tomorrow morning in Montreal, Laval and the South Shore of Montreal, Environment Canada said. 

It hasn't been that cold in Montreal since Jan. 14, 2018, when temperatures reached –27 C, according to the agency.

Meanwhile, local homeless shelters say they are desperate for volunteers, with COVID-19 threatening to overwhelm the system as temperatures drop to extreme lows starting Monday night.

Due to COVID-19 outbreaks among people experiencing homelessness in Montreal, there are fewer spaces available in the city's shelters and in warming centres, said  Émilie Fortier, the head of emergency services at the Old Brewery Mission.