Other facts from our historical weather data: When is winter in Hamar? The coldest season / winter is in the following months: January, February and December. Which is the warmest month in Hamar? July has an average maximum temperature of 21°C (70°F) and is the warmest month of the year. Which is the coldest month in Hamar? The coldest month is January with an average maximum temperature of -2°C (28°F). Which is the wettest month in Hamar? August tops the wettest month list with 108mm (4.3 in) of rainfall. Which is the driest month in Hamar? March is the driest month with 48mm (1.9 in) of precipitation. Which is the sunniest month in Hamar? 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.