Other facts from our historical weather data: When is the rainy season in Ossana? Rainy season in Ossana occurs in the months of May, June, July and August. When is winter in Ossana? The coldest season / winter is in the following months: January, February and December. Which is the warmest month in Ossana? July has an average maximum temperature of 18°C (64°F) and is the warmest month of the year. Which is the coldest month in Ossana? The coldest month is January with an average maximum temperature of -3°C (27°F). Which is the wettest month in Ossana? July tops the wettest month list with 224mm (8.8 in) of rainfall. Which is the driest month in Ossana? January is the driest month with 53mm (2.1 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.