São Paulo in June

April through September is your sweet spot. The weather is cooler and drier, perfect for walking around the city without melting. July can get surprisingly chilly (bring a jacket), but it's also when the cultural calendar explodes — film festivals, art exhibitions, and music events everywhere. October through March is summer, which means heat, humidity, and afternoon thunderstorms that can flood the streets. But the energy is electric during Carnaval season (February/March), even though São Paulo's celebration is more underground than Rio's. Avoid December and January if possible — half the city evacuates to the coast, and many restaurants close. The shoulder months of April and September offer the best balance of good weather and manageable crowds.