If you're hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Tres Lagoas: The hottest months are usually September and October with an average temp of 80°F, while the coldest months are June and July with an average of 72°F. The rainiest months in Tres Lagoas are January, December, February, and March, with each month seeing an average of 9 inches of rainfall.