Other facts from our historical weather data: Which is the hottest month in Mata de Sao Joao? February has an average maximum temperature of 32°C (90°F) and is the hottest month of the year. Which is the coolest month in Mata de Sao Joao? The coolest month is August with an average maximum temperature of 28°C (82°F). Which is the wettest month in Mata de Sao Joao? May tops the wettest month list with 142mm (5.6 in) of rainfall. Which is the driest month in Mata de Sao Joao? December is the driest month with 47mm (1.9 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.