San Juan weather in August
August in San Juan: sweltering, rainy, with clean air — a good time to visit.
#10 of 12 months in San Juan · #453 of 604 destinations to visit in August · comfort 66/100 (tier C)
Updated June 2026 · climate normals from ERA5 reanalysis
San Juan climate normals — August
| Daytime high | 32°C / 89°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 25°C / 77°F | |
| Feels like (high) | 36°C / 97°F | |
| Rainfall | 82 mm / 3.2 in | 🌧 rainy |
| Rainy days | 17 days | |
| Humidity | 80% | 💦 very humid |
| Dew point | 24°C / 75°F | |
| Sunshine | 11.1 h/day | |
| Daylight | 12.7 h | |
| Wind | 20 km/h / 13 mph | |
| Air quality (US AQI) | 34 | 🍃 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 August — FAQ
- Is August a good time to visit San Juan?
- August in San Juan: sweltering, rainy, with clean air — a good time to visit. It ranks #10 of 12 months for San Juan on SeasonMap's comfort score (66/100).
- What is the weather like in San Juan in August?
- In August, San Juan averages a daily high of 31.8°C and a low of 25.2°C, with about 81.6 mm of rain over roughly 17 rainy days.
- What is the air quality in San Juan in August?
- San Juan has a mean US Air Quality Index of about 34 in August.