Other facts from our historical weather data: Which is the warmest month in Riobamba? October has an average maximum temperature of 15°C (59°F) and is the warmest month of the year. Which is the coldest month in Riobamba? The coldest month is August with an average maximum temperature of 14°C (57°F). Which is the wettest month in Riobamba? March tops the wettest month list with 255mm (10 in) of rainfall. Which is the driest month in Riobamba? August is the driest month with 80mm (3.1 in) of precipitation. Which is the sunniest month in Riobamba? November is the sunniest month with an average of 105 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.