Weather will likely play an important role when you plan your trip to São Carlos, but bear in mind that cheaper options are usually available when the weather isn’t as good. The hottest months are usually September and October, with an average temperature of 23°C, while the coldest months are July and June, with an average of 19°C. The rainiest months in São Carlos are January, December, February and November, with each month seeing an average of 277 mm of rainfall.