Will Autumn Bring More 20-Degree Days?
As October progresses, the weather in Quebec appears to defy seasonal expectations. Several regions continue to experience temperatures around 20°C, which is becoming more common. This trend raises the question: will autumn bring more 20-degree days?
Increase in Late-Season Warm Days
In 2025, Quebec residents have witnessed warm temperatures that extend well into the autumn. On October 19, notable highs were recorded: 22.3°C in Montreal, 24°C in Sherbrooke, and an impressive 29°C in St-Anicet. Ottawa also set a record with a temperature of 26°C on the same day.
Changing Patterns of Autumn Weather
- Warm days beyond mid-October have become increasingly common.
- Since 2020, there has been a significant rise in temperatures exceeding 20°C after October 15, averaging more than four days each year.
- This is notably higher than in previous decades.
Looking ahead, Quebec is expected to experience temperatures slightly above normal in the coming weeks. However, the extreme south may be affected by cooler air from the eastern United States, limiting warm spells.
Historical Temperature Insights
Traditionally, reaching 20°C marks the end of summer and the onset of cooler autumn conditions. The average date for the last 20°C day is October 12, based on historical climate data. This data highlights the variability and changing nature of seasons within Quebec.
A Climate Shift
The occurrence of warm autumn days signals a broader climate change. Seasonal patterns are shifting, with longer autumns and delayed frosts becoming the norm. The frequency of 20°C days in October suggests a redefining of traditional seasonal boundaries.
As we reflect on these trends, the focus now lies on how far these new climatic patterns will extend the limits of what is considered typical for autumn weather in Quebec.
