Weather is probably a major factor when you plan your trip to São João del Rei, 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 21°C, while the coldest months are July and August, with an average of 17°C. The rainiest months in São João del Rei are December, January, November and February, with each month seeing an average of 248 mm of rainfall.