The best time to visit Dege is May through October, when the mountain passes are reliably open and the weather, though still cold at night, allows comfortable daytime travel. June and July are the wettest months, bringing afternoon storms that can reduce visibility and occasionally close roads for a day or two, but travel is still possible.
Winter travel to Dege is serious business. Snow closes the high passes between November and April, and the road from Ganzi to Dege can become impassable for days or weeks. Some travellers make it through in winter by taking lower-elevation routes, but this requires flexibility and an acceptance of potentially being stranded.
The most significant festival in the Dege region is the annual horse racing festival, typically held in late summer — August or early September. The plateau fills with nomads, there is considerable ceremony, and Dege itself sees an unusual concentration of Tibetan visitors from across the region.
Political circumstances can close Dege to foreign visitors at any time. Tibetan-majority areas in western Sichuan are subject to periodic access restrictions, particularly around politically sensitive anniversaries. Check current conditions before committing to travel here.