Winters in Skien are cold and dark, with January being the coldest month, averaging around -2°C. Temperatures fluctuate between -19°C and 8°C during this time. As winter gradually comes to an end, March brings slightly warmer temperatures, ranging from -9°C to 18°C, averaging around 4°C. Spring is a mild season, with April and May temperatures rising steadily, reaching highs of up to 28°C in May. Summer months are warm, but not hot, with July being the warmest month, averaging around 17°C, while September marks the beginning of autumn, with temperatures cooling down again.