In September, the weather in Bolshaya Usa is typically warm. Average daily high temperature in September is about 15 degrees above zero. On average, Bolshaya Usa has 13 rainy, 10 partly cloudy, 4 sunny, and 3 cloudy 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 Bolshaya Usa.