Experts are reminding people to stay cool and hydrated as humidex values near 40 C in parts of central and eastern Canada.

Parts of Quebec, Ontario, Manitoba, Newfoundland and Saskatchewan are expected to experience sweltering temperatures this weekend, according to Environment Canada, which issued more than 50 heat-related warnings across the country on Saturday. The warnings affected more than five million Canadians.

With temperatures nearing 30 C, B.C. could soon be added in the coming days.

"The most important things are staying hydrated with water preferably, and to get enough rest. That might mean resting a bit more than you would normally when you’re spending time outside," Dr. Heejune Chang of the Winnipeg Regional Health Authority told CTV Winnipeg.

High temperatures and humidity are also expected across Ontario throughout the weekend.

In Toronto, humidex values neared 40 C thanks to a hot, humid air mass. Temperatures were expected to significantly drop to the low 20s by the evening.

Ottawa was under a similar heat warning Saturday, with intense humidity and humidex values of 36 C.

A cold front is forecast to move through the region Monday night, bringing in a cooler and less humid air mass.

Daytime temperatures in southern Manitoba are set to climb as high as 32 C on Saturday. In Winnipeg, humidex values will make the city feel more like 39 C.

The extreme heat is expected to come to an end Saturday night when a cold front passes through the province, according to Environment Canada. Temperatures will return to a more tolerable 25 C high by Sunday.

An upper ridge of high pressure continues to give extreme heat to the southeast corner of Saskatchewan. However, a cold front is expected to pass through late Saturday afternoon.

Much of B.C. is also expected to be hit by high temperatures in the coming days. Outside of the city of Kamloops, hot conditions are making the work to contain wildfires more difficult, with crews working night and day to extinguish flames that have already razed more than 500 hectares and come frighteningly close to some homes.

Northern Ontario has also experienced hot temperatures, exacerbating already dry conditions in a region where wildfires are continuing to spread.

This year already, Canada has experienced twice as many days above 30 C than it did during the entire summer of 2017.

Kent Moore, an atmospheric physicist at the University of Toronto, said Canadians can expect scorching summers like this in the years ahead.

“The fact is the Earth is warming up. It’s been warming up for the last 40 years or so and it’s going to continue to warm up into the future. I think we can expect to see more extreme temperatures in the summertime and more heatwaves,” he said.

Environment Canada has advised people to seek out places where they can stay cool, such as shaded areas, swimming pools, or air-conditioned buildings.

They also asked that the public watch for the effects of heat illness. This includes swelling, rashes, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.

More than 50 people died in Quebec earlier this month after a record-breaking heat wave.

Authorities have asked members of the public to keep an eye on those who could be vulnerable to extreme heat.

“Typically what happens in heatwaves it’s the elderly and people with compromised health that are caused problems,” Moore added. “When it gets warmer it’s harder for the body to get rid of heat, so it stresses internal organs.”