Eastern Canada is currently experiencing an exceptional and unseasonal heatwave, with record-breaking temperatures recorded in Quebec and Ontario during the first week of October 2025. A powerful high-pressure system has driven temperatures up to 15°C above the seasonal average, creating conditions warmer than many U.S. cities. Montreal-Trudeau International Airport recorded a high of 29.9°C on October 5, 2025, surpassing the previous all-time October record set in 2023. Other locations also saw anomalous readings, including Saguenay at 29.2°C, Val-d'Or at 28.8°C, and Gatineau reaching 30.3°C. Even northern Quebec experienced unseasonably warm conditions, with Kuujjuaq nearing 20°C.
This unseasonal warmth has coincided with active fires north of Montreal, exacerbating air quality concerns. Canada has already endured a significant wildfire season in June and July 2025, with approximately 8.78 million hectares burned by mid-September, making it the second-worst season on record. The 2023 wildfire season was even more severe, burning approximately 17.6 million hectares. The combination of high temperatures and persistent drought conditions has contributed to this heightened fire activity.
Scientists attribute the increasing frequency and intensity of such extreme weather events, including heatwaves and wildfires, to human-caused climate change. Studies indicate that prolonged heatwaves dry out vegetation, creating more fuel for fires and increasing the likelihood of extreme fire weather. The 2025 wildfire season has been particularly devastating, with Manitoba and Saskatchewan accounting for over half of the area burned. The impacts of these fires extend beyond environmental damage, affecting public health and disrupting communities across the country.
While the immediate forecast suggests a return to more seasonal temperatures by Tuesday with the arrival of a cold front, the underlying conditions that foster such extreme events remain a concern. The prolonged dry spell in regions like Ottawa, receiving less than half its normal rainfall over the past three months, further highlights the vulnerability to fire. The ongoing pattern of unseasonable warmth and its connection to increased wildfire risk serves as a stark reminder of the evolving climate landscape.