As extreme heat grips southern Ontario, Environment Canada has issued an air quality warning for Toronto, with smoke from ongoing wildfires in northern Ontario contributing to poor air conditions.
The national weather agency says smoke is causing or is expected to cause poor air quality and reduced visibility, which could persist through the day and possibly into Tuesday for some areas.
“Smoke from forest fires over northern Ontario has moved into the area, causing the air quality to deteriorate significantly,” reads the air quality warning issued for Toronto.
Environment Canada is urging residents—particularly vulnerable groups—to take extra precautions.
Those most at risk from wildfire smoke include people aged 65 and older, pregnant individuals, infants and young children, those with existing illnesses or chronic health conditions, and people who work outdoors. Officials recommend that these groups avoid strenuous outdoor activities and seek medical attention if they experience symptoms such as coughing, difficulty breathing, or chest discomfort.
“You may experience mild and common symptoms such as eye, nose and throat irritation, headaches or a mild cough,” Environment Canada says. “More serious but less common symptoms include wheezing, chest pains or severe cough. If you think you are having a medical emergency, seek immediate medical assistance.”
A heat warning remains in place for Toronto after being issued over the weekend. Residents can find relief from the heat and humidity at more than 500 cool spaces across the city, including libraries, community centres, and air-conditioned civic buildings.
Ongoing wildfires in Saskatchewan, Manitoba, and northwestern Ontario continue to produce massive plumes of smoke that are actively filling the atmosphere. Since Jan. 1, 2025, more than 3,000 wildfires have burned over 5 million hectares across the country.
Today’s daytime high in Toronto is expected to reach 31 C, with the humidex values in the upper 40s. The air quality health index rating could get to 5 (indicating a moderate risk) in Toronto on Monday.
A scorcher is forecast for Tuesday with sunny skies and a daytime high of 32 C. The humidex is likely to reach 37 in Toronto on Tuesday, Environment Canada says.
Daytime temperatures could drop slightly by mid-week or Thursday, when cloudier conditions and the potential for rain move in. There is a 60 per cent chance of showers for Toronto on Thursday, with a daytime high of 29 C.
Toronto residents could get a break from the extreme heat by the end of the week, when daytime temperatures could drop to a high of 25 C.
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