Goiânia has a tropical savanna climate with two distinct seasons. The dry season runs from May to September — clear skies, temperatures between 20°C and 30°C, and low humidity make this the most comfortable time to visit. June and July are the coolest months, and nights can be genuinely cold (10–15°C), which surprises visitors expecting relentless tropical heat.
The wet season from October to April brings afternoon thunderstorms, high humidity, and occasional flooding of the lower-lying areas. The city turns dramatically green during the rains, and the cerrado surrounding Goiânia blooms into colours that justify a visit on their own terms. The Festa do Divino Pai Eterno in Trindade (30 km south) in early July is the largest religious festival in Brazil and draws millions of pilgrims — the city is overwhelmed, but it is a remarkable spectacle if you plan ahead.