Other facts from our historical weather data: Which months have the greatest rainfall in Rio Bianco? Most rainfall (rainy season) is seen in June, July and August. Which is the warmest month in Rio Bianco? 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 Rio Bianco? The coldest month is January with an average maximum temperature of -3°C (27°F). Which is the wettest month in Rio Bianco? June tops the wettest month list with 162mm (6.4 in) of rainfall. Which is the driest month in Rio Bianco? January is the driest month with 68mm (2.7 in) of precipitation. Which is the sunniest month in Rio Bianco? 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.