San Juan weather in January
January in San Juan: hot, a little rain, with clean air — one of the best months to visit.
#1 of 12 months in San Juan · #189 of 604 destinations to visit in January · comfort 79/100 (tier B)
Updated June 2026 · climate normals from ERA5 reanalysis
San Juan climate normals — January
| Daytime high | 28°C / 83°F | 🥵 hot |
|---|---|---|
| Nighttime low | 22°C / 71°F | |
| Feels like (high) | 30°C / 86°F | |
| Rainfall | 36 mm / 1.4 in | 🌦 some rain |
| Rainy days | 11 days | |
| Humidity | 78% | 💦 very humid |
| Dew point | 20°C / 68°F | |
| Sunshine | 10.3 h/day | |
| Daylight | 11.2 h | |
| Wind | 19 km/h / 12 mph | |
| Air quality (US AQI) | 32 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is San Juan?
Loading map…
San Juan in January — FAQ
- Is January a good time to visit San Juan?
- January in San Juan: hot, a little rain, with clean air — one of the best months to visit. It ranks #1 of 12 months for San Juan on SeasonMap's comfort score (79/100).
- What is the weather like in San Juan in January?
- In January, San Juan averages a daily high of 28.4°C and a low of 21.6°C, with about 35.7 mm of rain over roughly 10.6 rainy days.
- What is the air quality in San Juan in January?
- San Juan has a mean US Air Quality Index of about 32 in January.