Other facts from our historical weather data: Which months have the greatest rainfall in Arêches? Most rainfall (rainy season) is seen in May and December. When is winter in Arêches? The coldest season / winter is in the following months: January, February and December. Which is the warmest month in Arêches? July has an average maximum temperature of 20°C (68°F) and is the warmest month of the year. Which is the coldest month in Arêches? The coldest month is January with an average maximum temperature of -1°C (30°F). Which is the wettest month in Arêches? December tops the wettest month list with 164mm (6.5 in) of rainfall. Which is the driest month in Arêches? October is the driest month with 114mm (4.5 in) of precipitation. Which is the sunniest month in Arêches? 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.