Taking into account the local weather in Sao Joao do Sul can help you maximize your time at the pool during your trip. The hottest months are usually February and January with an average temp of 73°F, while the coldest months are July and June with an average of 61°F. The rainiest months in Sao Joao do Sul are September, January, October, and March, with each month seeing an average of 8 inches of rainfall.