Rarely has a heat wave of this intensity been recorded so early in June in Quebec.

And she hasn’t said her last word: cooler temperatures are not expected before Friday in the south of the province.

Such a heatwave is rarely observed this early in the summer.

“It is similar to the worst heat waves in July and August,” illustrated Jennifer Smith, meteorologist at Environment and Climate Change Canada, at a press briefing Wednesday afternoon.

Its particularity: it is not only hot, but “incredibly humid”. “Also, nighttime temperatures remain very warm. »

In Montreal, the mercury is expected to reach 34 degrees on Wednesday. A three-day streak with maximum temperatures of 32 degrees was only observed twice before June 20: in 1919 and 1978. And the heat record in June was in 1964, with 35 degrees.

“Records may be broken,” said Jennifer Smith.

Public health authorities reiterated on Wednesday the precautionary measures to take during periods of extreme heat.

“The current episode may present serious health risks,” said Éric Lavigne, Health Canada research scientist.

Seniors, infants, people with chronic illnesses, those who are homeless or who work outside are particularly at risk of heat stroke.

The list of symptoms to watch for includes dizziness, fainting, nausea, headache and extreme thirst.

“Heat stroke is a medical emergency. If you notice someone experiencing total or partial loss of consciousness, confusion, elevated body temperature, or no longer sweating, call 911 immediately,” he stressed.

With climate change, heat waves will become more frequent.

“Warming extends the period during which temperatures exceed a certain threshold,” explained Nathan Gillet, a research scientist at Environment and Climate Change Canada.