Most of southern Ontario can look forward to some relief from the heat, as cooler air is expected to arrive Tuesday night, said Environment Canada. 

But that reprieve from the heat may not be shared by the whole region, said a heat warning from the national weather agency.

Hot and humid conditions could continue into Wednesday for the Greater Toronto, Hamilton Area and eastern Ontario. 

In Toronto, daytime temperature highs will be around 33 C with humidity making it feel closer to 41 on Tuesday. Evening lows will be around 22 C. 

There’s also a chance of showers and a risk of thunderstorms expected Tuesday afternoon and evening in Toronto, said the agency’s website. 

On Wednesday, sunny skies with a chance for showers and thunderstorms is expected. The daytime high will be 30 C, but closer to 37 with humidity, and evening temperature lows will be around 18 C in Toronto. 

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Toronto Public Health reports 51 heat-related emergency room trips so far this month, more than in July 2024. Mayor Olivia Chow says more needs to be done to improve the city’s hot weather plan.

Environment Canada warns hot, humid air could also lead to worsening air quality. The air quality health index for Toronto was at 3, or “low risk,” as of Tuesday morning.

People are advised to drink water often, watch for signs of heat exhaustion and to check on those at-risk for heat illnesses, said the weather agency. 

It also suggests turning on air conditioning, using a fan and staying indoors to limit exposure to the heat.

“Heat warnings are issued when very high temperature or humidity conditions are expected to pose an elevated risk of heat illnesses,” said Environment Canada’s warning on Tuesday. 

Signs of heat stroke can include red and hot skin, dizziness and nausea.

Over 500 spaces across Toronto are available for residents looking to cool down during a heat warning, said the City of Toronto on social media.