Heat warning issued for Montreal Sunday through Tuesday, with humidex values as high as 45 C

Environment Canada has issued a heat warning for Montreal, with high temperatures above 30 degrees Celsius, and lows above 20, forecast for Sunday through Tuesday. Humidex values are due to hit between 40 and 45 degrees over the course of the three-day heat wave. Heat and humidity is expected to ease on Wednesday.

The heat warning notes that action should be taken to protect yourself and others as “extreme heat can affect everyone’s health.”

“Drink water often and before you feel thirsty. Close blinds or shades and open windows if outside is cooler than inside. Turn on air conditioning, use a fan, or move to a cooler area of your living space. If your living space is hot, move to a cool public space. Plan and schedule outdoor activities during the coolest parts of the day. Limit direct exposure to sun and heat. Wear lightweight, light-coloured , loose-fitting clothing and a wide-brimmed hat. Never leave people, especially children, or pets inside a parked vehicle. Check the vehicle before locking it to make sure no one is still inside.”

It’s also recommended to check in on seniors and others at greater risk of heat illness.

For more heat wave management tips, please visit this City of Montreal resource page.

Stay cool Montreal.

A heat warning and a special weather statement are currently in effect for southern Quebec. Humidex values between 40 and 45 are expected from Sunday to Tuesday. Plan your activities accordingly. For more details: https://t.co/jjao34veSH#QCstorm pic.twitter.com/1Imi1Nvter

— ECCC Weather Quebec (@ECCCWeatherQC) June 21, 2025

For the latest weather updates in Montreal, please visit the Weather Network.

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