San Juan · AutumnMonth summary
San Juan weather in September
✅ Good
🌡️ Temperature min / max
77°F – 88°F
🌧 Rainy days
74% of days
☀️ Sunshine
11.5h per day on average
🌊 🌊 Season
Autumn
⭐ ⭐ Weather score
7.1/10
📅 📅 Best month
January (8.0/10)
Quick decision
Should you visit San Juan in September?
✅ Good
✅ Yes if: you're willing to accept showers in exchange for lower prices and fewer tourists.
❌ No if: you're planning 100% outdoor activities — rain is frequent.
Our take: San Juan in September: 88°F and 11.5h of sunshine. Decent, but not the peak.
By trip type
San Juan in September by trip type
- 🏙️ 🏙️ City break / culture : ✅ Good
- 🚶 🚶 Outdoor activities : ⚠️ Possible
- 🏖️ Beach / swimming : ⚠️ Possible
- 💰 💰 Budget : ✅ Low season
Local context
What to expect in September
Autumn in San Juan is often underrated: 31°F, golden light and declining crowds. An interesting window. With 74% of rainy days, always have indoor alternatives planned. Not the best window, but acceptable if dates are constrained. January (8.0/10) is significantly better if possible.
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All months for San Juan
Annual table
Month-by-month comparison
| Month | Min °F | Max °F | Rain % | Precip in | Sun h/d | Score |
|---|---|---|---|---|---|---|
| 🌤️ January | 72°F | 82°F | 47% | 0.1in | 10.9h | 8.0/10 |
| 🌤️ February | 72°F | 82°F | 55% | 0.1in | 11.0h | 7.8/10 |
| 🌤️ March | 72°F | 82°F | 53% | 0.1in | 11.2h | 7.9/10 |
| 🌤️ April | 73°F | 84°F | 59% | 0.1in | 12.1h | 7.6/10 |
| 🌤️ May | 75°F | 86°F | 59% | 0.1in | 12.6h | 7.5/10 |
| 🌤️ June | 77°F | 88°F | 56% | 0.1in | 12.9h | 7.5/10 |
| ⛅ July | 77°F | 88°F | 67% | 0.1in | 12.7h | 7.3/10 |
| ⛅ August | 77°F | 88°F | 65% | 0.1in | 12.1h | 7.2/10 |
| ⛅ September | 77°F | 88°F | 74% | 0.2in | 11.5h | 7.1/10 |
| ⛅ October | 75°F | 86°F | 71% | 0.2in | 11.2h | 7.2/10 |
| ⛅ November | 75°F | 84°F | 67% | 0.2in | 10.7h | 7.3/10 |
| 🌤️ December | 73°F | 82°F | 57% | 0.1in | 10.8h | 7.7/10 |
Ideal
Fair
Challenging climate
◀ Current month · Source Open-Meteo · 10 years
📊 Data source
Data based on 10 years of ERA5 records via Open-Meteo, with ECMWF seasonal adjustment. In September, San Juan averages 88°F, 74% rainy days and 11.5h of sunshine per day. Overall weather score: 7.1/10.
See methodology →
Comparison
September vs January (best month)
The best month is January (score 8.0/10). Difference:
- 🌡️ Max temperature : -3°F
- 🌧 Rainy days : -27%
- ☀️ Sunshine : -0.6h/day
FAQ
FAQ — San Juan in September
Is September a good time to visit San Juan?
September is an acceptable time for San Juan (score 7.1/10). Conditions are decent but not optimal — consider January (8.0/10) if possible.
Does it rain a lot in San Juan in September?
Yes, 74% of days see rain in September. Plan some indoor activities as backup.
Accommodation
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Activities & tours
Activities and tours in San Juan
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