The heat dome that has been hovering over parts of the country shattered an overnight temperatures record in Toronto on Thursday (Friday NZT), and the heat wave flirted with other record highs across Eastern and Central Canada.

In Windsor, Ont., a high of 39 degrees Celsius was predicted, making it the hottest city in the country. By mid-afternoon, the city felt like 50 C with the humidity.

Environment Canada released a special weather statement for the region on Thursday, warning residents that a “sultry tropical air mass” will make its way across all of southern Ontario by the afternoon.

Windsor’s highest-ever temperature of 40.2 C was set on June 25, 1988.

And in Hamilton, the mercury reached 36 C, just below the city’s old high of 37.4 C.

Meanwhile, in Canada’s largest city, officials reissued an extreme heat alert warning Torontonians to try to stay cool as the temperatures continue to climb.

Temperatures in Toronto hit a high of 38 C, although baseball fans at Thursday’s Blue Jays game at the Rogers Centre got some reprieve from the sweltering heat as the retractable roof was closed for the game.

Thoroughbred racing at the city’s Woodbine Racetrack were cancelled because of concerns for the horses’ safety.

Toronto’s downtown record sits at 40.6 C, which was set during a 1936 heat wave. The record at the Pearson International Airport is 38.3, which was set in 1948. Record-keeping only started at the airport in 1937.

Across Ontario, heat alerts have been issued in several areas including the Niagara region, Waterloo and Cornwall.

In the nation’s capital, the mercury hit 36 C.

Forecasters predicted highs of 34 C in Montreal and 31 C in Fredericton.

Environment Canada’s senior climatologist Dave Phillips noted that what’s remarkable about this prolonged heat blast is that temperatures aren’t dipping overnight.

Several places in Ontario, including Toronto, London and Hamilton, saw their hottest nights ever.

For Torontonians who woke up at 6 a.m. it was already 27.1 C Thursday.

“Back in the famous heat waves of the past you could always count on the nights cooling off so the body could build back,” Phillips said.

“What’s becoming more characteristic of our kind of heat waves now is not so much the excruciating high temperatures, it’s the elevated minimum temperatures.”

Phillips told CTV’s Canada AM on Thursday that the heat dome, a hot, stagnant high-pressure area, is presently hanging over central parts of Canada and keeping cooler or wetter weather out.

“It’s almost like a bully, it just doesn’t move,” he said. “Any type of cold, fresh, Canadian cold waves are just blocked from coming in.”

According to an Environment Canada warning preparedness meteorologist, the heat dome phenomenon happens every few summers.

“Every day it gets hotter and hotter,” Marie-Eve Giguere told The Canadian Press. “It gets heat from the sun and this sort of hot dome air is getting hotter and hotter and this is what’s creating these high temperatures.”

The dome is currently sitting over much of the United States. It spread up to Western Canada over the weekend, covering large swaths of the country and pushing the temperatures to scorching highs in the Prairies.

On Tuesday, Winnipeg was baking under a high of 34.4 C and Regina under 31.9 C.

Looking ahead, the 10-day forecast predicts above-normal temperatures from eastern Alberta through to Prince Edward Island.

– Canadian Television (CTV)