The hot and humid weather sitting over southern Quebec prompted Enviroment Canada to issue a heat warning that will likely last until Wednesday.
In Montreal the forecast is expected to reach a high temperature of 32 C, but with high relative humidity levels it will feel much worse.
There is a chance of thunderstorms throughout the day on Monday, and possibly overnight as well when the temperature drops to 22 C.
The muggy mess will stick around on Tuesday with a slightly lower temperature expected, but it won't feel any nicer. Thunderstorms are also possible on Tuesday.
The humidity will move on by Wednesday, and daytime temperatures will reach 27 to 28 C while overnight lows will drop to the upper teens.
Fifty-three people died in Montreal during a heat wave in July.
Public Health agencies are advising people who are outside to take it easy and to avoid strenuous activity.
At pools in Montreal, lifeguards told people to get out of the sun at least once an hour and to ensure patrons drank plenty of fluids.
People who do not have air conditioning in their homes are being advised to seek out malls, libraries, community centres, or other areas that are cool.
Authorities are reminding drivers to never leave children, the elderly or pets unattended in a car, even with the windows open.
As of Monday there are 110 heat warnings in effect across the country, although the criteria is different in each region.
Environment Canada’s David Phillips warns that the extreme temperatures seen around the world in recent months will be the norm for this time of year in decades to come and that this summer’s weather is a "dress rehearsal" of what is to come.
Halifax’s heat warning was expected to linger until Wednesday or Thursday, with daytime highs around 30 C and maximum humidex values as high as 40.
