Extreme heat warning issued for Toronto, Peel, Hamilton and GTA

Environment Canada has issued a heat warning for Toronto and much of the Greater Toronto Area, with dangerously hot and humid conditions expected to begin on Monday and continue until Wednesday or Thursday evening.

According to the weather agency, daytime temperatures are forecast to reach between 30C and 36C, with humidex values ranging from 38 to 45 while Tuesday is expected to be the hottest day of the heat event.

"Tuesday will mark the peak of this heat event. Maximum temperatures are expected to reach near 36 degrees Celsius in some areas," Environment Canada said.

The agency also warned that "Hot and humid air can also bring deteriorating air quality and can result in the Air Quality Health Index approaching the high-risk category."

The warning covers Toronto, Peel, Halton, Hamilton, Niagara, Vaughan, Richmond Hill, Markham, Pickering and Oshawa.

Environment Canada urged residents to stay hydrated and watch for signs of heat-related illness.

"Watch for the early signs of heat exhaustion in yourself and others. Signs may include headache, nausea, dizziness, thirst, dark urine and intense fatigue. Stop your activity and drink water”, officials said.

The City of Toronto has activated its Heat Relief Strategy, opening cooling spaces at civic centres and providing a 24-hour cool space at 136 Spadina Road.