Weather is probably a major factor when you plan your trip to Rio Dulce, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and May with an average temp of 80°F, while the coldest months are January and February with an average of 74°F. The rainiest months in Rio Dulce are November, July, October, and August, with each month seeing an average of 15 inches of rainfall.