Other facts from our historical weather data: Which is the warmest month in Gressan? 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 Gressan? The coldest month is January with an average maximum temperature of -4°C (25°F). Which is the wettest month in Gressan? November tops the wettest month list with 134mm (5.3 in) of rainfall. Which is the driest month in Gressan? February is the driest month with 92mm (3.6 in) of precipitation. Which is the sunniest month in Gressan? July is the sunniest month with an average of 275 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.