The summer of 2025 is particularly violent in Quebec

Is the weather particularly violent this summer? Between heat waves, torrential rains, and poor air quality, the weather isn't giving much respite to Quebecers trying to enjoy the "beautiful season." And we'll have to get used to it, experts warn: these episodes are just a glimpse of what awaits us in the future.

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"Severe weather, storms and heat waves are major climate issues in Quebec that will not improve in the future," warns UQAM hydroclimatology professor Philippe Gachon.

As forests burn in Western Canada, Montreal and Quebec City ranked among the most polluted cities in the world last weekend due to smog generated by the blazes.

• Also read: Here's why Canada is burning, but not Quebec

At the same time, Environment Canada issued a heat warning for the southern part of the province. The humidex exceeded 35 degrees Celsius (°C) in some areas.

Last week, record amounts of water fell in several cities in a matter of hours. The torrential rains caused sewer backups, flooding, and landslides in the Quebec City region.

In June, the average temperature across the province exceeded normal "for the 28th consecutive month," reports the Ministry of the Environment. Three tornadoes also swept through Centre-du-Québec, Estrie, and Chaudière-Appalaches during that month.

No more great heat

It's difficult to predict what the weather will be like in Quebec in the coming summers.

"There is variability. Some summers are sometimes drier than others. Temperature variations are normal from one year to the next and within the same season," says Simon Legault, meteorologist and science communicator at Ouranos.

One thing is clear, however: the number of very hot days will continue to rise.

From 2015 to 2024, an average of 277 weather stations across the country recorded temperatures of 30°C or higher, according to data from Environment and Climate Change Canada. From 1999 to 2014, the average was 199.

Since the start of the summer season, some regions of Quebec have already recorded 15 days with temperatures exceeding 30°C. The norm is around a dozen per year, Mr. Legault said.

"We must prepare for the future," he says. "Even if we drastically reduced greenhouse gas emissions overnight, the impacts of global warming will continue to be felt for decades to come."

Twice as fast

These effects are likely to be more visible in Quebec, given that the province is warming nearly twice as fast as the global average.

"The northern regions, near the poles, are warming more quickly. This is called polar amplification. The ice melts, giving way to darker water that absorbs more of the sun's energy," explains Simon Legault.

And with this warming, the multiplication of periods of meteorological variability is inevitable.

Climate whiplash

"Climate change is amplifying the very rapid and marked alternation between extremes. And this is affecting our summers. Suddenly, we experience a dry period followed by torrential rains or ground frost, followed by extreme heat. We are losing the consistency of weather conditions normally associated with the season," explains Professor Philippe Gachon.

"In addition, we are in an area prone to whiplash , to climate whiplash," he adds.

This new term, which has recently appeared in the climatological lexicon, refers to the sudden succession of extreme weather events.

While these phenomena used to occur decades apart in the past, they now occur back-to-back. And if global warming reaches 3°C, these whiplashes are likely to double.

The planet is on track to reach 2.7°C of warming by 2100.

More water, but more droughts

"One of the consequences of global warming is that it disrupts the volatility of the precipitation regime: a warmer atmosphere can hold more moisture," Gachon illustrates.

For each degree of increase in global temperature, the atmosphere will contain 7% more water.

"We realize that in summer conditions, short-term heavy rainfall increases much more rapidly than long-term rainfall. It is this rainfall that is responsible for flooding and landslides," says the hydroclimatology expert.

But the twist is that these torrential rains do not reduce droughts. Quite the opposite, in fact.

The higher the temperature rises, the faster water evaporates from the ground surface. Since the amount of additional precipitation is not enough to compensate for the loss of moisture, the risk of drought also increases.