Anytime is a good time to visit Southern France. Summer (Jul–Aug) is one long salvo of festivals, fairs, and fireworks. In spring (Apr–June) and fall (Sept–Nov) the weather is still gorgeous, and the coastline is warm enough for both swimming and sunbathing. As the Riviera is averages 300 days of sun per year, winter (Dec–Mar) can also be splendid. Furthermore, with hardly a tourist in sight, you’ll be welcomed as an honorary local. Prices of hotels and restaurant menus fall out of season, sometimes dramatically.
Inland it’s a slightly different story. Many museums, stores, and hotels shut up shop entirely from November until Easter. Provence in particular dreads le mistral (an unrelenting wind), which most often blows in the winter for bouts of a few days at a time, but can also last up to 2 weeks. That said, cities like Avignon and Aix-en-Provence are at their most hauntingly beautiful during that chilly period. Cool weather also slathers snow across the ski resorts north of Nice.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.