In September, the weather in Zheleznogorsk-Ilimsky is typically cold. Average daily high temperature in September is about 9 degrees above zero. On average, Zheleznogorsk-Ilimsky has 14 rainy, 6 sunny, 6 cloudy, and 4 partly cloudy days in September. The rains are usually moderate. September as well as January, February, April, and May is considered the most uncomfortable time to visit Zheleznogorsk-Ilimsky.