Taking into account the local weather in Sao Joao do Oeste can help you maximize your time at the pool during your trip. The hottest months are usually January and February with an average temp of 76°F, while the coldest months are July and June with an average of 60°F. The rainiest months in Sao Joao do Oeste are October, May, June, and December, with each month seeing an average of 9 inches of rainfall.