September in Montreal offers a transition from summer’s warmth to autumn’s crispness. Typical daytime temperatures range from 15C to 20C (59F to 68F), with cooler nights dipping down to around 10C (50F). This period experiences decreasing humidity and sunshine hours, with an increasing likelihood of rainfall compared to the preceding summer months. Packing layers is recommended to adapt to the fluctuating temperatures between day and night.
This time of year presents an ideal balance for enjoying outdoor activities and exploring the city. The pleasant weather allows for comfortable sightseeing, hiking on Mount Royal, or strolling through the city’s parks and botanical gardens as the foliage begins its transformation into vibrant autumn hues. Historically, September has marked the return to routine after the summer holidays, and the city comes alive with cultural events and festivals, offering a unique experience for visitors.