An Environment Canada heat warning said temperatures would remain high all weekend, just in time for crowds to flock to outdoor festivals in the city.
The agency said high humidex values would make the air feel like it was near 40 C, and could feel even hotter than that in crowded areas.
“The feeling of discomfort will be particularly acute in urban areas, where temperatures could reach a few degrees higher,” the warning said.
The heat will increase the risk of heat exhaustion or heat stroke, the agency said. It urged people to drink lots of water.
The heat warning, issued early Friday morning, coincided with the start of Osheaga weekend, a music festival in Parc Jean-Drapeau that is expected to draw 150,000 people. Organizers of the festival said water will be available on site and said attendees should bring their own water bottle.
Pride organizers also said there would be water fountains available at all of their outdoor events. August is Pride month in Montreal and the festival began this week with events centred near Place des Festivals and in the Village.