In September, the weather in Mo i Rana is typically cold. Average daily high temperature in September is about 8 degrees above zero. On average, Mo i Rana has 21 rainy, 5 sunny, 3 cloudy, and 1 partly cloudy day in September. The rains are usually heavy. September as well as May, June, July, and August is considered the most uncomfortable time to visit Mo i Rana.