Other facts from our historical weather data: Which is the warmest month in Onich? 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 Onich? The coldest month is December with an average maximum temperature of 7°C (45°F). Which is the wettest month in Onich? January tops the wettest month list with 233mm (9.2 in) of rainfall. Which is the driest month in Onich? April is the driest month with 128mm (5 in) of precipitation. Which is the sunniest month in Onich? May is the sunniest month with an average of 189 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.