What to know
Environment Canada has issued a cold weather warning for Toronto, with overnight lows near –22 C and wind chills making it feel closer to –30 C this weekend.
A UHN emergency physician warns that frostbite can lead to amputation if untreated, urging residents to watch for skin colour changes, numbness, and severe pain when rewarming.
Hypothermia risks rise during extreme cold, particularly for children, older adults, and unhoused people, as the City of Toronto opens warming centres and adds shelter spaces.
A Toronto health expert is giving out tips for identifying and avoiding frostbite and hypothermia ahead of a cold front that’s about to make the city feel like -30 C this weekend.
Environment Canada has issued a yellow warning for Toronto, as the city braces for “bitterly cold conditions” from Friday evening into Saturday morning. The cold front could bring a low of -22 C overnight, with the wind chill making it feel closer to -30 C to -33 C.
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Despite making it tempting to stay inside, University Health Network’s (UHN) Deputy Emergency Department Medical Director Dr. Kate Hayman says temperatures that cold can create serious risks for frostbite and hypothermia.
FROSTBITE RISKS AND TREATMENT
According to Hayman, frostbite is a localized injury caused by the cold, which can even lead to amputations if left untreated.
“It’s really important that the public is aware of the risks when it’s colder than -10 C, or if people are exposed to the cold and are also wet,” she told Now Toronto on Friday.
To identify frostbite, the doctor says Torontonians should watch out for changes of colour or sensation on the skin, which could become tingly or numb, and extremely painful when rewarmed.
“Any change in colour is concerning. Initially, when people are exposed to the cold before the area is rewarmed, the area tends to go very, very pale. With mild frostbite, we see a red colour, kind of like a sunburn and sometimes blisters. And with severe frostbite, the skin often gets gray or dusky or black with bloody blisters,” she said.
Those who spot signs of frostbite should immediately look for shelter and try to warm up the area. If the numbness or colour change doesn’t go away, they should look for help as soon as possible.
“They [can] immerse the affected part in warm water—not boiling water—but sort of like a warm, bath temperature for about 30 minutes until the area starts to feel soft,” she said.
“After that, if they’re still concerned…would be a good time to see a doctor in an emergency room or at a clinic, because early treatment of frostbite is really important to help prevent amputations.”
HYPOTHERMIA RISKS AND TREATMENT
Contrary to frostbite, which typically affects one specific area of the body, hypothermia happens when a person’s full body temperature drops too much due to cold exposure.
According to the Medical Council of Canada, hypothermia happens when body temperature falls below 35 C, while severe hypothermia is when it reaches 28 C.
“People tend to have a lot of shivering, as the body tries to rewarm itself. But when people get very, very cold, they tend to become sleepy, drowsy, sometimes unconscious, and they can also have heart rhythm problems,” Hayman said.
“In the most severe cases, it can cause the heart to stop.”
If they notice any of these symptoms, residents should immediately get inside, make sure to stay dry and try to warm up by wrapping themselves in blankets, drinking warm liquids, and moving their muscles.
If their temperature drops by 2 C to 4 C, or below 32 C, residents are advised to seek emergency services immediately, as advised by the Government of Canada.
WHO IS AT RISK?
Hayman says every person has an individual resistance to cold, which depends on their own abilities to manage their symptoms, with risk groups including children and older adults.
“If you’re a healthy young adult, and you go to shovel the snow, and it takes you 45 minutes and you’ve got mittens on, you’re probably at relatively low risk,” she said.
“A child or an infant or an older adult or someone who is intoxicated or otherwise not able to communicate [are at a higher risk] because those people may start to experience some of that pain and colour change that are those early warning signs, and they aren’t able to communicate it to get out of the cold right away.”
In Toronto, people who are usually admitted to the emergency room with hypothermia or frostbite symptoms are disproportionately unhoused, according to Hayman.
“People who are experiencing homelessness, who don’t have anywhere to shelter, or people who might be intoxicated or who for mental health reasons, are at higher risk of being outside for a long period of time,” she said.
The doctor advises that these people should be directed to shelters or warming centres during periods of extreme cold.
In response to the cold warning, the City of Toronto’s Warming Centres remain open, with another 117 new spaces being added in its shelter programs.
In response to the extreme cold, the City’s -5 and -15 Warming Centres and surge spaces remain open. Today, the City and its partners have added another 117 spaces in shelter programs to help get as many people inside as possible.
Enhanced street outreach teams continue to… pic.twitter.com/kxRMyXUgUc
— City of Toronto 🇨🇦 (@cityoftoronto) January 23, 2026