One hundred heat warnings were in effect across Canada Tuesday afternoon, with more possible as hot weather prepared to settle in the Prairies.

The number of warnings issued by Environment Canada had fallen from Monday due to cooling temperatures in southern Ontario and Quebec. All heat warnings had ended in both provinces.

Temperatures in southern Ontario were expected to remain in the high 20s – above normal August values but slightly below heat warning levels – for the rest of the week.

Heat warnings continued to cover all of New Brunswick, Nova Scotia and Prince Edward Island, as well as parts of Newfoundland and Labrador.

Environment Canada warned that much of the Maritimes would see highs between 29 C and 32 C on Tuesday, with humidex values potentially topping 40. Similar conditions were expected on Wednesday, with cooler weather in the forecast for Thursday and beyond once tropical moisture leaves the region.

“They’ll be able to get back to sleeping and not putting the air conditioning on [by Thursday],” Environment Canada senior climatologist David Phillips told CTV News Channel on Tuesday.

A high-pressure ridge was bringing hot air into parts of Western Canada, where heat warnings were in effect for areas including Vancouver, Calgary and Edmonton.

Highs around 30 C were expected to persist until Friday in Vancouver and until Saturday in Calgary and Edmonton.

In Calgary, Phillips said, temperatures could hit 34 C or 35 C at their peak.

“That’s a dozen degrees warmer than it should be for this time of the year,” he said.

The hot weather was then set to make its way across the Prairies, with forecasts calling for daytime highs to reach or surpass 30 C in southern Saskatchewan and southern Manitoba starting on Wednesday.

The heat event in those provinces would likely last for four or five days, Environment Canada said.

Phillips cautioned that most of the country would continue to see hotter weather than normal for much of the rest of the summer.

“Our forecast for August into September is showing more heat, heat, heat from coast to coast,” he said.