Buenos Aires is in the southern hemisphere, so the seasons are reversed from Europe and North America. The best times to visit are spring (September–November) and autumn (March–May), when temperatures are in the 15–25°C range and humidity is manageable. The parks and streets are at their most pleasant; outdoor dining, which is the city's default mode, is comfortable.
Summer (December–February) is hot and humid, with temperatures regularly exceeding 35°C. Much of the city's professional class leaves for the beach at Mar del Plata or Punta del Este in January, which makes the city quieter but also somewhat reduced in energy. Air conditioning is universal; outdoor markets and street activity slow during the hottest part of the day.
Winter (June–August) is mild by most standards — temperatures rarely drop below 5°C — and the city continues at full pace. There is virtually no snow. Winter can be grey and damp, but the cultural calendar (theatre, opera, tango) is at its peak, and hotel prices are lower than in peak season.
The Buenos Aires Tango Festival (usually August) is the best time to see tango performed and taught by the city's leading practitioners; milongas and outdoor performances run throughout the week-long festival.