September in Cannes typically offers a pleasant transition from the summer heat to milder autumn conditions. Average high temperatures hover around 24C (75F), while lows dip to a comfortable 17C (63F). The Mediterranean Sea retains warmth from the summer months, making swimming still enjoyable. Rainfall is possible, but generally less frequent and intense than in later autumn or winter. Sunshine hours decrease slightly compared to August, yet remain substantial.
This period provides ideal conditions for various activities. The still-warm sea allows for watersports, while the cooler air makes land-based explorations, such as hiking or cycling, more agreeable. The lessening crowds compared to peak season contribute to a more relaxed atmosphere. Historically, September has marked the beginning of the grape harvest in the surrounding Provence region, adding a unique cultural dimension to a visit.