Other facts from our historical weather data: When is the rainy season in Uderns? Rainy season in Uderns occurs in the months of May, June, July, August and September. When is winter in Uderns? The coldest season / winter is in the following months: January, February and December. Which is the warmest month in Uderns? August has an average maximum temperature of 19°C (66°F) and is the warmest month of the year. Which is the coldest month in Uderns? The coldest month is January with an average maximum temperature of -1°C (30°F). Which is the wettest month in Uderns? June tops the wettest month list with 212mm (8.3 in) of rainfall. Which is the driest month in Uderns? January is the driest month with 92mm (3.6 in) of precipitation. Which is the sunniest month in Uderns? May is the sunniest month with an average of 185 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.