Other facts from our historical weather data: Which is the warmest month in Granvin? July has an average maximum temperature of 17°C (63°F) and is the warmest month of the year. Which is the coldest month in Granvin? The coldest month is February with an average maximum temperature of -1°C (30°F). Which is the wettest month in Granvin? January tops the wettest month list with 226mm (8.9 in) of rainfall. Which is the driest month in Granvin? May is the driest month with 102mm (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.