If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Goiania: The hottest months are usually September and October, with an average temperature of 25°C, while the coldest months are July and June, with an average of 22°C. The rainiest months in Goiania are December, January, February and November, with each month seeing an average of 234 mm of rainfall.