May, June and September are the sweet spots. The weather is warm without the August heat, the markets are at their best, and the Dordogne countryside is in good shape for day trips. July and August are busy with French and Dutch holidaymakers heading south; rooms in town are tight and the cave sites at Lascaux and Les Eyzies need to be booked weeks ahead.
Winter is cool and quiet but has one big advantage: truffle season. From mid-November to early March the place Saint-Louis hosts a Saturday morning truffle market, and most of the better restaurants in town put truffle menus on the chalkboard.
The city's biggest event is Mimos, an international mime and physical-theatre festival held over five days in late July or early August, with free performances in squares across the old town.