Autumn (September–November) is the best time to visit Chinle and Canyon de Chelly. Temperatures are moderate, the cottonwood trees on the canyon floor turn gold, and the light in the canyons is extraordinary. The Navajo Nation Fair at Window Rock, a two-hour drive south, takes place in early September.
Spring (April–May) is also good, with wildflowers on the canyon floor and mild temperatures. Summer brings intense heat and afternoon thunderstorms that can make the canyon floor impassable with flash floods — a real danger that guides take seriously. Winter is cold, and some rim drive sections may be icy, but snowfall transforms the canyons into something surreal and beautiful, and visitor numbers are very low.