September in Lanzhou averages a daily high of 20.3°C with nights around 8.2°C. Expect roughly 13 wet days totalling 70.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Lanzhou is April–September.
Based on YU ZHONG, CH (35km), 1995–2024. 14 years of September data.