A heat warning is in effect for Toronto and surrounding regions as hot and humid weather blankets the city for a second straight day.
Environment Canada says temperatures will rise above 30 C again today, with lows in the 20s providing "little relief from the heat" tonight, before cooler temperatures arrive Wednesday.
"The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors," the federal weather agency says. "Reduce your heat risk. Schedule outdoor activities during the coolest parts of the day."
Heat warnings are issued when temperatures or humidity are expected to increase the threat of heat stroke or heat exhaustion, the agency says.
In Toronto, the city is activating its "heat relief network," which consists of 300 cool spaces, including libraries, community centres and pools, to provide relief for residents amid the heat warning.
The network also includes shelters and 24-hour respite sites open to those experiencing homelessness.
A map of cooling centres across the city can be found here.
Meanwhile, provincial transit agency Metrolinx is advising commuters to prepare for possible delays and cancellations on Tuesday as crews conduct heat patrols throughout the day to check on signs of "sun kinks" on its railway tracks.
The agency says the patrols are necessary during prolonged periods of heat with temperatures above 30 C as the steel tracks can soften and expand, "potentially creating conditions that make it unsafe to run trains at high speeds."