A punishing heat wave has descended upon Eastern Canada this week, with temperatures soaring well above seasonal norms across Ontario and Quebec. Toronto recorded a blistering 34°C on Wednesday, feeling more like 42°C with humidity—conditions that meteorologists warn will persist through the weekend with little overnight relief.
“We’re looking at a sustained period of dangerous heat that will affect millions of Canadians,” said Dr. Eleanor Vaughn, climate scientist at Environment Canada. “What makes this particularly concerning is the duration and the limited overnight cooling, which prevents homes and bodies from recovering.”
The heat dome—a high-pressure system trapping warm air—has settled over the Great Lakes region, creating what health officials describe as potentially life-threatening conditions for vulnerable populations. Montreal has activated its extreme heat protocol, opening cooling centers throughout the city as temperatures there reached 35°C, with humidity making it feel nearly 10 degrees warmer.
In Ottawa, where the temperature hit 33°C by noon Thursday, paramedic services reported a 27% increase in heat-related emergency calls compared to typical summer days. “Dehydration and heat exhaustion cases are climbing rapidly,” confirmed Ottawa Paramedic Service spokesperson Jean Tremblay.
This marks the second major heat event for the region this summer, following a shorter but equally intense spell in early July. Climate experts at the University of Toronto’s Department of Atmospheric Physics note this pattern aligns with broader climate change projections for Eastern Canada.
“What we’re witnessing is consistent with climate models that predict more frequent and prolonged extreme heat events,” explained Dr. Aamir Khan, climatologist at the university’s CO24 News research partner program. “Historically, the Toronto-Montreal corridor might experience two or three days above 33°C annually. We’re now regularly seeing week-long stretches multiple times each summer.”
Power consumption has surged to near-record levels as air conditioners run continuously. Hydro Quebec issued a conservation appeal Wednesday, requesting residents limit electricity use during peak periods to prevent grid strain. Ontario’s Independent Electricity System Operator reported demand approaching 24,000 megawatts—close to the province’s all-time summer peak set during the 2006 heat wave.
Local governments across the affected regions have implemented emergency measures. Toronto has extended pool hours and opened designated cooling centers in community buildings. Montreal authorities are conducting wellness checks on elderly residents living alone, a practice implemented after the deadly 2018 heat wave that claimed 66 lives across Quebec.
Health Canada advises that even healthy individuals should limit outdoor activities, particularly during peak afternoon hours. “Heat illness can develop rapidly, sometimes within 30 minutes of exertion in these conditions,” warned Dr. Maria Santos of Health Canada’s Environmental Health Division in an interview with CO24 Canada.
Agricultural impacts are also mounting. The Ontario Federation of Agriculture reports that dairy production has declined approximately 15% in affected areas, while fruit growers express concern about potential crop damage if the heat persists. “When temperatures remain above 30°C for extended periods, even irrigated crops struggle,” noted François Delorme, agricultural economist at McGill University.
Meteorologists predict a cold front will finally break the heat by early next week, though another system may develop by mid-August. As extreme weather patterns become increasingly common across the country, the question remains: is Canada’s infrastructure—from power grids to emergency services—adequately prepared for what climate scientists warn will become the new normal?
