July in Rjukan is the warmest month of the year. In July, the weather in Rjukan is typically warm. Average daily high temperature in July is about 14 degrees above zero. On average, Rjukan has 19 rainy, 5 sunny, 4 cloudy, and 3 partly cloudy days in July. The rains are usually heavy. July as well as April, May, June, and August is considered the most uncomfortable time to visit Rjukan.