August in Ust-Omchug is the rainiest month of the year. In August, the weather in Ust-Omchug is typically warm. Average daily high temperature in August is about 14 degrees above zero. On average, Ust-Omchug has 10 rainy, 8 partly cloudy, 7 sunny, and 6 cloudy days in August. The rains are usually moderate.