Québec is bracing for a summer marked by intense heat, relentless humidity and an increased risk of violent storms, according to the long-range forecast from MétéoMédia. As of Monday, May 26, 2025, the heat dome phenomenon is expected to dominate the weather patterns across Eastern Canada, particularly affecting Québec, Ontario and the Maritimes.
Persistent heat and omnipresent humidity in Québec
A heat dome, a broad zone of high atmospheric pressure trapping warm air at ground level, will anchor itself over central North America. This will result in higher-than-normal temperatures in Québec, compounded by what forecasters describe as “omnipresent humidity.”
According to André Monette from MétéoMédia, this means nights in Québec will be especially stifling, with moisture-laden air preventing any significant cooling after sunset. The prolonged heat periods, paired with high dew points, are likely to create ideal conditions for severe thunderstorms.
Stormy skies ahead: violent storms and changing air masses
Because Québec lies on the eastern flank of the heat dome, it will be vulnerable to frequent cold fronts sweeping down from the northwest. These shifting air masses are expected to trigger multiple storm events throughout the season.
Monette warns that these systems may produce “vigorous cold fronts” capable of sparking violent storms, including strong winds, large hail, and the potential for tornados. The clash between hot, humid air and colder, drier air aloft could intensify storm development significantly.
Other regional forecasts: Maritimes, Western Canada and national implications
To the east, the Maritimes will also see above-average temperatures and precipitation, with the 2025 hurricane season predicted to be active, possibly compounding storm threats and rainfall totals.
To the west, Western Canada will not escape the heat either. Above-normal temperatures, combined with below-average precipitation, elevate the risk of wildfires in the Prairies and British Columbia. The dry conditions, in tandem with potential smoke from forest fires, may affect air quality across the country, including parts of Québec.
No Indian summer: September will bring a shift
Despite the hot and humid conditions expected for June, July and August, the warmth is not expected to carry over into September. MétéoMédia forecasts a cooler, more autumnal trend as early fall arrives, bringing relief from the summer’s oppressive heat.
This upcoming Québec summer is shaping up to be oppressive, dynamic and potentially hazardous, requiring close monitoring of severe weather alerts in the months ahead.
