Rio de Janeiro vs Buenos Aires

Based on sunshine hours, rain days, comfortable temperatures, and humidity levels, Buenos Aires edges ahead as the better destination in January. Buenos Aires offers 12 hours of daily sunshine with only 7 rain days, while Rio de Janeiro sees 10 sunshine hours and 20 rain days.

Rio de Janeiro can feel quite hot at 31°C, so plan for heat. Buenos Aires is also comfortable at 28°C.

For travelers who prioritize dry weather, Buenos Aires is the stronger choice in January. Buenos Aires receives 2 more hours of sunshine per day, which matters for sightseeing and outdoor activities.

Rio de Janeiro reaches an average high of 31°C (88°F) and drops to 24°C (75°F) at night during January. The daily temperature range is 7°C, meaning relatively stable temperatures from day to night.

Buenos Aires averages 28°C (82°F) for the high and 20°C (68°F) for the low, with a daily range of 8°C. The 3°C difference is noticeable but not dramatic.

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

Rio de Janeiro receives approximately 253 mm of rainfall across 20 rain days during January. Rain is frequent, so waterproof gear is essential.

Buenos Aires sees 88 mm over 7 rain days. That makes Buenos Aires the drier option by 13 rain days and 165 mm of total precipitation.

Humidity also differs: Rio de Janeiro averages 78% while Buenos Aires sits at 70%. Rio de Janeiro will feel muggier, especially at higher temperatures.