The Greater Toronto Area and other parts of southern Ontario are under a heat warning as temperatures are expected to reach up to 35 C today.
Environment Canada says it could feel like up to 44 C across a stretch of the province bordering Lake Ontario from St. Catharines to Toronto.
The weather agency says nighttime low temperatures of 20 to 23 C will provide relief from the daytime heat.
Environment Canada says temperatures are expected to decrease on Friday to near 30 C, with a humidex value of up to 40 C.
It's not the first heat warning for Ontario this summer — extreme heat reaching the mid-30s broke temperature records in many parts of the province last month.
During extreme heat events, people are advised to drink water often, watch for signs of heat exhaustion and to check on older adults and those at risk of heat illness.
This report by The Canadian Press was first published July 24, 2025.
The Canadian Press
