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 September. Buenos Aires offers 4 hours of daily sunshine with only 4 rain days, while Rio de Janeiro sees 4 sunshine hours and 12 rain days.

Buenos Aires sits in the comfortable travel range at 16°C. Rio de Janeiro runs hot at 30°C.

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

Buenos Aires reaches an average high of 16°C (61°F) and drops to 8°C (46°F) at night during September. The daily temperature range is 8°C, meaning moderate variation throughout the day.

Rio de Janeiro averages 30°C (86°F) for the high and 23°C (73°F) for the low, with a daily range of 7°C. There is a notable 14°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 September.

Buenos Aires receives approximately 50 mm of rainfall across 4 rain days during September. Rain is occasional, so a light rain jacket should suffice.

Rio de Janeiro sees 140 mm over 12 rain days. That makes Buenos Aires the drier option by 8 rain days and 90 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.