Weather is probably a major factor when you plan your trip to Barretos, 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 77°F, while the coldest months are June and July with an average of 70°F. The rainiest months in Barretos are January, December, November, and March, with each month seeing an average of 9 inches of rainfall.