San Juan weather in May
May in San Juan: sweltering, a little rain, with clean air — a great time to visit.
#6 of 12 months in San Juan · #459 of 604 destinations to visit in May · comfort 71/100 (tier B)
Updated June 2026 · climate normals from ERA5 reanalysis
San Juan climate normals — May
| Daytime high | 31°C / 89°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 24°C / 75°F | |
| Feels like (high) | 35°C / 95°F | |
| Rainfall | 50 mm / 2 in | 🌦 some rain |
| Rainy days | 10 days | |
| Humidity | 78% | 💦 very humid |
| Dew point | 22°C / 72°F | |
| Sunshine | 11.5 h/day | |
| Daylight | 13 h | |
| Wind | 19 km/h / 12 mph | |
| Air quality (US AQI) | 30 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is San Juan?
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San Juan in May — FAQ
- Is May a good time to visit San Juan?
- May in San Juan: sweltering, a little rain, with clean air — a great time to visit. It ranks #6 of 12 months for San Juan on SeasonMap's comfort score (71/100).
- What is the weather like in San Juan in May?
- In May, San Juan averages a daily high of 31.4°C and a low of 23.8°C, with about 49.9 mm of rain over roughly 9.6 rainy days.
- What is the air quality in San Juan in May?
- San Juan has a mean US Air Quality Index of about 30 in May.