The caves are open year-round, but summer (July–August) is the hardest time to visit: Font-de-Gaume's limited tickets sell out weeks in advance, and the Vézère valley becomes busy with French domestic tourists. The best time to come is May–June or September–October. The weather is mild, the crowds are manageable, and you have a realistic chance of getting a ticket for Font-de-Gaume on short notice.
Spring is particularly beautiful in the valley: walnut trees in leaf, the river running clear, the limestone cliffs glowing in slanted light. Autumn brings the walnut harvest, local markets, and the prospect of truffles. In winter the caves are open but some restaurants close; it's quiet and atmospheric, and Font-de-Gaume tickets are easy to obtain.