September on the French Riviera!
September and October in Antibes
In terms of weather, fall isn't the best time to visit the French Riviera. Though temperatures are comfortable, with temperatures hovering in the 60s and extending into the lower 70s on warmer days, storms and rainy days are common. You can still visit many of the beautiful markets, antique fair and really enjoy the French Riviera. It is also a great time of year to go property hunting as selling agemts have more time to spend with cleints and its not uncomfortable warm. October is far and away the wettest month, followed by November and September. That said, if you do have a sunny couple of days, it's almost warm enough to swim, especially since the Mediterranean water temperature—having heated up all summer long—is in the warm 70s.
The summer crowds typically clear out by the first or second week of September, meaning cheaper rates on hotel rooms (and less need to make restaurant reservations). Still, special events like the Régates Royales sailing regatta, which takes place in September, bring an influx of visitors to the region. The cooler months mean you can expolre Antibes, Cannes and St Tropez in a better temperature and less crowds.