A heat warning is in effect for Toronto and surrounding regions as humid weather blankets the city for a second straight day.
Environment Canada says temperatures are predicted to rise above 30 C again on Sunday, with humidex values expected to be in the mid to high 30s.
"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.
"Drink plenty of water even before you feel thirsty and stay in a cool place."
Heat warnings are issued when temperatures or humidity are expected to increase the threat of heat stroke or heat exhaustion, the agency says.
The heat warning is expected to end on Sunday evening with the passage of a cold front.