TORONTO: A blast of late winter cold triggered warnings across southern Ontario’s most populous corridor as March began, with Environment and Climate Change Canada issuing a Yellow Warning – Cold at 7:58 p.m. EST Sunday, March 1, for parts of the region. The agency said wind chill values of -25 to -30 were forecast overnight into Monday morning, March 2, raising the risk of frostbite for anyone spending time outdoors. The warning was posted for multiple forecast areas and remained in effect early Monday as temperatures fell sharply under clear skies.

Environment Canada listed affected communities from the Greater Toronto Area west through Hamilton and areas around Halton and Waterloo, and east into southern Durham. Local forecasts for Toronto, Mississauga, Markham and Hamilton carried the same alert language, urging residents to cover exposed skin and limit time outside during the coldest hours. The agency said the risks were greater for young children, older adults, people with chronic illnesses, those working or exercising outdoors and people without proper shelter. It also warned that pets should not be left outside if conditions were too cold for people.
By early Monday, readings underscored the sharp chill. At 2 a.m., Toronto City Centre Airport reported a temperature of -10.9 degrees Celsius with a wind chill of -16, while Toronto Pearson International Airport measured -13.1 C at the same hour. The Guelph Turfgrass Institute reported -16.5 C. In Hamilton, the airport reported -13.6 C and the local forecast called for a low of -18 C with wind chill near -25 overnight. Environment Canada said some parts of southern Ontario could feel closer to -30 when wind is factored in.
Cold warning spans major communities
Municipal services pointed residents to indoor spaces as the warning took hold. Burlington Public Library said a cold warning for Halton Region beginning March 1 made all open branches official community warming centres during operating hours, allowing people to sit indoors and warm up. The library said pets could come inside with their owners, with visitors directed to designated areas when needed. Environment Canada’s warning urged residents to keep moving to maintain body heat and seek shelter from the wind. The agency said frostbite can develop within minutes on exposed skin during severe wind chill.
The cold alert carried an impact level listed as moderate with high forecast confidence in Environment Canada’s bulletin. The agency’s alert system now uses colour coding across all warnings, advisories and watches, a change introduced late last year to help residents gauge risk at a glance. In the Toronto area, the agency’s hourly forecast showed clear skies overnight Monday with temperatures around -17 to -18 C and wind chill values in the low to mid -20s before daytime sunshine pushed readings higher. The warning window extended into Monday morning, with officials urging continued monitoring of updates.
Forecast calls for gradual warmup
Forecasts issued Sunday afternoon showed the cold snap easing after the start of the workweek. Environment Canada’s outlook for Toronto Island called for a sunny Monday high of -5 C, followed by clear skies Monday night near -8. For Tuesday, the forecast turned to a chance of snow or rain with highs near 3 C. In Hamilton, the agency forecast a Monday high of -3 C, then a similar mix of precipitation Tuesday with a high of 2 C. Nearby communities west of Toronto were forecast to reach 4 to 5 C by Wednesday as cloud cover increased.
Environment Canada said the cold posed a health risk even for healthy adults, particularly with wind and prolonged exposure, and advised wearing layers, covering hands and face and taking breaks indoors. The agency also urged residents to check on people without adequate shelter and to ensure pets are brought inside during extreme wind chill. In its bulletin, the agency said frostbite can develop within minutes on exposed skin, especially when wind chill values fall below -25. Alerts remained posted for several southern Ontario forecast regions early Monday as conditions moved through the overnight period. – By Content Syndication Services.
