Other facts from our historical weather data: Which is the warmest month in Hafjell? July has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in Hafjell? The coldest month is December with an average maximum temperature of -4°C (25°F). Which is the wettest month in Hafjell? August tops the wettest month list with 128mm (5 in) of rainfall. Which is the driest month in Hafjell? February is the driest month with 52mm (2 in) of precipitation. Which is the sunniest month in Hafjell? June is the sunniest month with an average of 243 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.