Buenos Aires vs Rio de Janeiro

Based on sunshine hours, rain days, comfortable temperatures, and humidity levels, Buenos Aires edges ahead as the better destination in December. Buenos Aires offers 7 hours of daily sunshine with only 6 rain days, while Rio de Janeiro sees 7 sunshine hours and 18 rain days.

Buenos Aires sits in the comfortable travel range at 25°C. Rio de Janeiro runs hot at 32°C.

For travelers who prioritize dry weather, Buenos Aires is the stronger choice in December.

Buenos Aires reaches an average high of 25°C (77°F) and drops to 17°C (63°F) at night during December. The daily temperature range is 8°C, meaning moderate variation throughout the day.

Rio de Janeiro averages 32°C (90°F) for the high and 25°C (77°F) for the low, with a daily range of 7°C. There is a notable 7°C gap between the two cities, so expect a very different feel.

Both cities are in the Southern Hemisphere, so they share the same seasonal pattern in December.

Buenos Aires receives approximately 70 mm of rainfall across 6 rain days during December. Rain is occasional, so a light rain jacket should suffice.

Rio de Janeiro sees 210 mm over 18 rain days. That makes Buenos Aires the drier option by 12 rain days and 140 mm of total precipitation.

Humidity also differs: Buenos Aires averages 65% while Rio de Janeiro sits at 78%. Rio de Janeiro will feel muggier, especially at higher temperatures.