If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Cachoeira do Sul: The hottest months are usually January and February, with an average temperature of 24°C, while the coldest months are July and June, with an average of 15°C. The rainiest months in Cachoeira do Sul are October, September, July and May, with each month seeing an average of 180 mm of rainfall.