Planning for the weather is a good way to make your trip to Goiania relaxing and enjoyable, especially when you’re splurging. The hottest months are usually September and October with an average temp of 77°F, while the coldest months are July and June with an average of 72°F. The rainiest months in Goiania are December, January, February, and November, with each month seeing an average of 9 inches of rainfall.