Published on August 19, 2025 at 11:21 a.m.
Summer has not said its last word: another heat thrust should mark Quebec towards the end of the week. It will be less painful than the previous ones. Forecast.
A striking summer
Two words can describe the summer of 2025 in southern Quebec: thunderstorms and heat. Both often go hand in hand, because heat and humidity give energy to stormy cells. We therefore had several particularly violent storm episodes in the beautiful province this summer.
As of August 19, we recorded 22 days with a maximum of at least 30 ° in Montreal in 2025. We are talking about almost double the average which is 12 days with such a maximum. In Quebec, Mercury has reached the 30 ° nine times mark while the average is six times. There has also been a 50 % increase in Saguenay, with 12 days at 30 ° or more, while the average is 9 days.
More reasonable heat
After a wave of particularly fresh nights (we even curled the freezing point in Lake Benoît, in Jamesie), the heat will be back in the coming days. But this time, no thunderstorms on radars, and much more reasonable feelings. The heat will go up from the south, but the air will be less full of humidity. So we are talking about a much less overwhelming heat. No formation of thunderstorm cells are provided after this short heat push.
Upward
Temperatures will start their ascents on Wednesday. It will continue on Thursday to reach a summit Friday and Saturday. In southern Quebec, the maximums could flirt with the 30 ° bar Friday and Saturday. We are talking about a maximum of 28 ° Friday and Saturday in Montreal. In Gatineau, the maximum will be 28 ° Friday and 29 ° Saturday. In Sherbrooke and Quebec, the maximum planned is 27 ° on Saturday.
Abitibi and Saguenay will not be outdone. The maximum should reach 26 ° Friday in Val-d’Or, and 25 ° Saturday in Saguenay. In Chibougamau, Mercury should reach 22 ° or 23 ° Thursday, Friday and Saturday. The North Shore is the only region that will not see the thermometer point at 20 ° or more. The maximum should not exceed 16 ° at Sept-Îles Thursday, Friday and Saturday.
If the trend is maintained
If the mercury reaches 30 ° in the metropolis during this wave, this will propel the summer of 2025 into the top 5 Montreal of a heat record for Montreal. It would indeed be the 23rd day of the year with a maximum of 30 ° or more, which would equal the mark of 2005. Only summers of 2020, 1959, 1949 and 1955 experienced more days with a maximum of 30 ° or more. The summer of 1955 seems to be out of reach with 33 days when Mercury reached or exceeded the 30 ° mark. But with heat trends in recent years, no record seems to be shelter.
With the collaboration of Mathias Ponton, meteorologist.