In September, the weather in Ust-Kamchatsk is typically warm. Average daily high temperature in September is about 12 degrees above zero. On average, Ust-Kamchatsk has 11 rainy, 9 partly cloudy, 6 sunny, and 4 cloudy days in September. The rains are usually moderate. September as well as May, June, August, and October is considered the most uncomfortable time to visit Ust-Kamchatsk.