January in Mount-Hagen is the rainiest and the cloudiest month of the year. In January, the weather in Mount-Hagen is typically warm. Average daily high temperature in January is about 17 degrees above zero. On average, Mount-Hagen has 31 rainy days in January. The rains are usually heavy. January as well as February, March, April, and May is considered the most uncomfortable time to visit Mount-Hagen.