If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Caxias do Sul: The hottest months are usually January and February with an average temp of 69°F, while the coldest months are July and June with an average of 55°F. The rainiest months in Caxias do Sul are October, September, January, and May, with each month seeing an average of 8 inches of rainfall.