Weather will likely play an important role when you plan your trip to Tres Lagoas, and keep in mind that cheaper options are usually available when the weather isn't as good. 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.