In September, the weather in Ust'-Yansky natsional'nyy nasleg is typically cold. Average daily high temperature in September is about 5 degrees above zero. On average, Ust'-Yansky natsional'nyy nasleg has 10 cloudy, 9 partly cloudy, 6 sunny, 4 rainy, and 1 snowy day in September. The rains are usually light.