Ürümqi has a continental desert climate of considerable extremes. Summers are scorching — temperatures regularly exceed 35°C in July and August — and winters are brutal, dropping to -15°C or colder. The city is surrounded by desert and sits far from any ocean, which means there is very little to moderate either season. Spring and autumn are the sweet spots.
April and May bring mild temperatures (15–25°C), clear skies, and the markets full of the season's dried fruit. September and October are even better: the summer heat has broken, the Tian Shan above Tianchi turns golden, and there is a sharpness to the air that makes hiking and sightseeing genuinely pleasant. These are the months when the city is most rewarding to visit.
The Naadam festival — a celebration of Mongolian and Kazakh nomadic culture featuring wrestling, archery, and horse racing — takes place in summer, typically July and August, in various locations around Xinjiang. The heat is punishing, but if you can find a Kazakh Naadam gathering (rather than a staged tourist event), it is worth the discomfort. Ask locally about timing, as the dates shift year to year.