TORONTO — Environment Canada has issued a heat warning for southern Ontario, saying hot and humid conditions could last into next Thursday.
The alert issued Friday morning says daytime highs for areas between Windsor and Cornwall are expected to range from 29 C to 32 C, with the humidex making it feel like it's 35 C to 40 C.
Overnight lows are expected to provide little relief, ranging from 19 to 23 degrees.
The weather agency says the hottest day is expected to be Saturday and a shift in weather patterns on Thursday is expected to end the long stretch of heat and humidity.
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 is the third heat warning issued for southern Ontario this summer, including extreme heat that broke records in June.
This report by The Canadian Press was first published July 11, 2025.
The Canadian Press
