Heat Waves: Information & Facts

The sun in the sky over a skyline with the power outThough Canada is known for its frosty winters, temperatures can get very high in the heart of summer. Prolonged exposure to extreme heat has serious medical risks, like heat cramps, heat exhaustion and heat stroke. 

Preparing for Heat Waves: Before, During & After

Heat Wave Basics 

Heat waves are an extended period of extreme heat. Environment Canada issues heat warnings at different temperatures depending on the region. For typically warmer climates, like southern Ontario, a heat warning will be issued after at least two days of a humidex of 42C or higher. Whereas in Labrador, there will be a heat warning after only an hour of the humidex reaching 40C. 

The people most at risk of heat stroke and heat exhaustion are the elderly and those with certain illnesses and health conditions. For these vulnerable populations, exposure to extreme heat can even be life-threatening. 

Heat waves can occur anywhere in Canada, though are most common in southern regions of the country. Extreme heat is most common in the summer, between June and September. 

Local governments will plan for heat waves by opening cooling centres throughout the area. Learn how to keep your family healthy and happy during the hottest days of the year. 

Environment Canada’s Public Weather Alerts keep you up-to-date on heat waves in your area. You can also stay up-to-date with local weather forecasts. 

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