January in San Juan averages a daily high of 28.8°C with nights around 21.1°C. Expect roughly 17.8 wet days totalling 116mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit San Juan is November–April.
Based on TOA BAJA LEVITTOWN, PR US (7.4km), 1995–2024. 16 years of January data.