September in Xining is the rainiest month of the year. In September, the weather in Xining is typically warm. Average daily high temperature in September is about 15 degrees above zero. On average, Xining has 20 rainy, 5 sunny, 3 cloudy, and 2 partly cloudy days in September. The rains are usually heavy. September as well as May, June, August, and October is considered the most uncomfortable time to visit Xining.