South Region in May

April through September delivers the region's best weather — warm days, cool nights, and minimal rain. São Paulo's concrete jungle becomes bearable when temperatures hover around 20°C instead of the sweltering 35°C summers bring. Rio's beaches are less crowded but still warm enough for swimming. This is festival season too: São Paulo's Virada Cultural happens in May, while Rio's Rock in Rio typically runs in September. Winter (June-August) means perfect hiking weather in the mountains around Curitiba and Gramado. But here's the catch: hotel prices spike during school holidays in July. If you can handle summer heat and crowds, December through March offers the classic Brazilian beach experience, plus Carnival season.