The best time to visit Altay Prefecture depends on what you are after. Summer — June to August — is the main tourist season, when the Kanas Lake area is fully open, roads are passable, and the alpine meadows are intensely green. This is also when Chinese domestic tourism peaks; Kanas can feel busy in July and August, especially on weekends.
September and early October are arguably the finest weeks in the calendar. Crowds drop sharply after the summer holiday season, the birch and larch forests around Kanas turn brilliant gold and red, and the light is extraordinary. The weather stays mild well into September.
Winter brings deep snow and extreme cold — temperatures in the mountains regularly drop below -30°C. The Kanas area closes to most visitors, but winter sports enthusiasts come to ski at the Altay Mountain Ski Resort near Altay City, and a few adventure travelers seek out the Tuvan villages in their full winter isolation.
Spring is unpredictable. The snow melts, roads become muddy, and some roads and facilities don't reopen until late May.