Planning for the weather is a good way to make your trip to Sao Caetano do Sul relaxing and enjoyable, especially when you're splurging. The hottest months are usually February and January, with an average temperature of 23°C, while the coldest months are July and June, with an average of 18°C. The rainiest months in Sao Caetano do Sul are January, February, December and March, with each month seeing an average of 302 mm of rainfall.