In September, the weather in Ust-Silayka is typically warm. Average daily high temperature in September is about 11 degrees above zero. On average, Ust-Silayka has 18 rainy, 10 cloudy, and 2 sunny days in September. The rains are usually moderate. September as well as January, February, April, and October is considered the most uncomfortable time to visit Ust-Silayka.