Most of Brazil  boasts a tropical climate, which means that you’ll encounter warm temperatures year-round, particularly in the Northeast  and the Amazon . Bahia , Alagoas, and Pernambuco each have rainy seasons (May–August). Wet seasons (May–December) in the Amazon and Pantanal  last for six months.
The South is the only region that has a real “winter,” which you’d probably rather avoid unless you’re in the mood for fondue and fireplaces. Summers can be sweltering, particularly in Rio  and São Paulo . Ultimately, the best times to visit the Southeast and South are March–June and September–November.
The other main consideration is high-season vs. off-season. During the summer Brazilians take long holiday weekends and inevitably head to the closest beach. The biggest exodus takes place from late December through Carnaval, and there’s another in July. During these times, all beaches, mountain resorts, and eco-destinations fill up. Accommodation prices can rise by up to 50 percent, and plane tickets need to be purchased in advance. Summer means heat, crowds, and higher prices, but it’s also when Brazil  kicks into high gear with intense party scenes and multiple festas.
If you prefer tranquility and like your beaches and mountains remote and secluded, then plan your trip to coincide with off-season. You’ll discover Brazilians in a less revved-up state, and in otherwise touristy areas, the diminished hustle and hassle can be very welcome.