Environment Canada issued a heat warning Tuesday morning for the Montreal area as the humidex continues to climb toward 40.
The warning was also issued for Gatineau and the Lanaudière region north of Montreal.
In Montreal, the temperature on Tuesday is expected to reach 28 C with a humidex of 37. On Wednesday, the humidex will reach or even surpass 40.
Environment Canada issues a heat warning when very hot or humid conditions may present a high risk of heat-related illnesses, such as heat stroke and heat exhaustion.
The agency recommends scheduling outdoor activities during the coolest parts of the day in order to reduce those risks.
Environment Canada forecasts high temperatures until Sunday, but the specific humidex values for the rest of week are not yet clear.