Hot, hot, hot: Heat warnings in effect across most of Canada's major cities

No matter where you live in Canada, it’s a good time to stay hydrated and think of ways to beat the warm weather.

Environment Canada has issued heat warnings across most of the country’s major cities, including Vancouver, Toronto, and Montreal.

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Vancouver is facing a strong ridge of high pressure that’s expected to bring elevated temperatures from Wednesday to Sunday morning, with daytime highs reaching anywhere from 29°C to 38°C.

Toronto and Montreal are both being plagued with high humidity, and it’s expected to feel close to 40°C in both cities with the humidex. While an official warning isn’t in place yet, highs in the low 30s are expected in Calgary this weekend.

Armel Castellan, an Environment Canada meteorologist, tells Daily Hive that it’s not just the major cities that are feeling the effects of the heat.

“You’re going to see that happen over Regina, Saskatoon, Winnipeg… they’ll likely be under heat warnings by the weekend,” he explains in an interview.

And naturally, each city is being affected by the heat in different ways. Toronto and Montreal, for example, are experiencing a flux of humidity that stems from the Gulf of Mexico. The heat seen on the West Coast of Canada is mainly from a strong ridge of high pressure.

“The heat comes from several different things,” Castellan says. “You need to have a ridge of high pressure. You have to think of it as putting a lid on the atmosphere so that it’s not really moving anywhere. You’ve got a ridge, it’s sitting there, it’s locked in place, and what you have underneath it is stagnant air that isn’t really able to move.”

“And not only that, but the heat builds from day to day and night to night, and that’s why it becomes so dangerous. It’s kind of a cumulative effect.”

Humidity adds another level of discomfort, increasing overnight temperatures and, in many cases, making it more difficult for a person’s body to release sweat and lower body temperatures.

“The humidity plays a big factor,” Castellan explains. “To have an air mass that has humidity that’s generated in the tropics makes a huge difference. Anyone that’s travelled to Quebec and Ontario in the summer knows instinctively when it’s so humid you can’t sweat the same way, so it doesn’t cool you off.”

“Right now Montreal has 60% humidity, the temperature is 30.4°C, but the humidex is at 40°C, so that’s very uncomfortable.”

Environment Canada and provincial health officials remind Canadians to drink plenty of water and stay hydrated, even before they feel thirsty. Additionally, check on individuals who may be more vulnerable to high temperatures, such as young children, pregnant people, older adults, and people with chronic illnesses.