Other facts from our historical weather data: Which is the warmest month in Mehamn? July has an average maximum temperature of 14°C (57°F) and is the warmest month of the year. Which is the coldest month in Mehamn? The coldest month is February with an average maximum temperature of -1°C (30°F). Which is the wettest month in Mehamn? October tops the wettest month list with 103mm (4.1 in) of rainfall. Which is the driest month in Mehamn? May is the driest month with 61mm (2.4 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.