Humidex values in Toronto, Ottawa and Montreal are expected to make it feel into the mid-40s in the coming days, putting the young and elderly at increased risk of dying from the heat.

The humidex values is best thought of as what it can feel like and is typically given without any degrees or reference to Celsius.

With expected “excruciatingly hot temperatures,” Environment Canada senior climatologist Dave Phillips told CTV News Channel “it certainly looks like a roasting-kind-of, furnace-like weekend for a large chunk of eastern Canada.”

He said the temperatures would be between five and eight degrees higher than average temperatures for this time of year.

Phillips predicted that, by Thursday night, there would be heat warnings for most of southern, eastern and central Ontario, the majority of Quebec and the Maritimes including New Brunswick and southern Nova Scotia.

The Weather Network’s chief meteorologist Chris Scott told CTV News Channel that the peak temperatures are expected to occur on Friday and Saturday.

Phillips said the hot weather should linger until Monday and Tuesday of next week. He said Canadians are in the “dog days of summer” now.

Temperatures in Ontario cities such as London and Windsor and Quebec cities such as Montreal, are all expected to hit the mid-20s during the evenings. Phillips said he was most concerned with the heatwave affecting people at night.


Youth, elderly, those with chronic diseases most at risk

Dr. David Kaiser with Montreal Public Health explained that the people most at the most risk are the young, the elderly, people with chronic diseases such as heart or lung conditions, and people with mental health issues.

“The important thing is that they are more at risk because they may be alone at night or in places where they don’t have air conditioning or cool spaces,” Kaiser said.

Kaiser explained that the temperatures could prove fatal for these groups. Sixty-six people died from heat-related incidents in Montreal last year.

Scott said a big reason for this was because the city was filled with old buildings without centralized cooling systems. Kaiser had recommendations for people to stay cool in general.

“The risk of heat is mostly from dehydration over the course of several days and the stress that that puts on the body,” he said, advising people stay out of the sun as much they could, cool down with wet towels and drink plenty of water.

He urged people to keep track of the potentially vulnerable. “Check on your family, check on your neighbours, check with people who are most at risk,” Kaiser said. Scott agreed and said, in these cases, this is “when we lose lives.”

Phillips said the one saving grace is that affected areas in Canada won’t be as humid as our neighbours to the south.

The forecasted muggy weather was because of high pressure systems travelling from western and eastern United States which Phillips said were pumping “warm, desert air and tropical air across the United States into southern Canada.”

He said people in two-thirds of the United States “can’t escape it,” with residents being affected in places including the U.S. states of Tennessee, the Carolinas and Illinois.

Scott said other parts of the country won’t be spared the heat once Sunday rolls around.

He said Canadians should expect to see a “switcheroo” after the weekend, in which the mugginess will be felt in places like Victoria and Kamloops, B.C, after places in Eastern Canada cool off.