Most of southern Ontario is warned for hot and humid weather over the weekend

Much of southern Ontario is under a heat warning that is expected to last through the weekend.

Environment Canada issued a heat warning Saturday morning, valid through Saturday and Sunday, warning Humidex levels are expected to hit the low 40s.

“High temperatures are expected to be in the low 30’s and minimum temperatures in the low to mid 20’s, providing little relief from the heat,” the alert said.

The heat warning has been issued in the vast majority of southern Ontario, including Toronto, Ottawa, London and Hamilton.

Only five areas in southern Ontario – Algonquin, Burk’s Falls – Bayfield Inlet, Parry Sound – Muskoka, Haliburton and Gray – Bruce – have not been placed under a heat warning.

The agency said the air quality health index was nearing its high-risk category due to the hot and humid air.

The public is reminded to drink plenty of water and watch for signs of heat illness, including swelling, a rash, cramps and fainting.

“Outdoor workers should take regularly scheduled breaks in a cool place,” Environment Canada said.

Cooler temperatures are forecast for Monday.