January in San Juan averages a daily high of 30.5°C with nights around 21.1°C. Expect roughly 3.9 wet days totalling 17.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit San Juan is January–February.
Based on SCIENCE GARDEN, RP (4.1km), 1995–2024. 27 years of January data.