Other facts from our historical weather data: Which months have the greatest rainfall in Hafslo? Most rainfall (rainy season) is seen in January, February, September, October and December. Which is the warmest month in Hafslo? July has an average maximum temperature of 18°C (64°F) and is the warmest month of the year. Which is the coldest month in Hafslo? The coldest month is December with an average maximum temperature of -2°C (28°F). Which is the wettest month in Hafslo? December tops the wettest month list with 179mm (7 in) of rainfall. Which is the driest month in Hafslo? May is the driest month with 95mm (3.7 in) of precipitation. 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.