Puerto Rico San Juan Weather in September — Climate Guide
September in San Juan is low
September is low for San Juan.
September is statistically San Juan's hurricane peak month + year's lowest tourist arrival month. Hotel pricing at year's absolute lowest. The trade-off is real: 25-35% chance of hurricane disruption during any given September week + sargassum reality + daily heavy storms.
Hurricane Maria (September 20, 2017, Category 4) was the canonical PR hurricane reminder — 3,000+ deaths, 11-month power outage in worst-hit areas, infrastructure still recovering in pockets. The island is resilient but September travelers should travel with insurance + flexibility.
Travel score
Hurricane peak + lowest pricing + Hurricane Maria 7th anniversary (Sept 20)
September Weather at a Glance
September averages 90°F / 32°C highs and 75°F / 24°C lows with 13 rainy days and 160mm rainfall — wettest month. Humidity 80%. UV 10. Sunshine 7 hours. Sea 29°C. Hurricane risk statistically peak. Hurricane Maria Sept 20, 2017 Cat 4 (anniversary year). Heavy storms reliable.
September Travel Advice
Travel insurance with hurricane cancellation + interruption coverage mandatory. NHC alerts subscription. Hotel hurricane evacuation procedures on check-in. Hurricane Maria anniversary (Sept 20) — memorial events at Old San Juan. Lowest pricing of year. Labor Day Weekend (1st Mon): book 4-6 weeks ahead.
Flying In from Overseas
Year's lowest international arrivals. Direct flights from NYC $200-350, Boston $200-350, Toronto $300-550, London via Madrid $500-800. European autumn shoulder begins. Korean + Japanese visitors minimal.
September Pricing Trends
Year's lowest: Condado oceanfront 4-star $130-240/night, La Concha + Condado Vanderbilt $180-380, El Convento $180-350. Vieques + Culebra -40% from peak. Some boutique hotels close mid-month.
San Juan September Weather Stats
Avg High
32°C
Avg Low
24°C
Rainy Days
13
160mm total
Sunshine
7h
Daily avg
Humidity
80%
very-humid
UV Index
10
Very high
Wind
19 km/h
Gusts 34
Sea Temp
29°C
swimming-warm
Crowds
Quiet
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
22 μg/m³
PM10
38 μg/m³
Status
moderate
Feels-Like Temperature & Wind
Feels like
Daytime
35°C
Nighttime
25°C
Humidity and wind affect how the actual temperature feels.
Wind
19 km/h
Max gust 34 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Year's lowest hotel pricing (-50-60% off peak)
- Labor Day Weekend brief social spike
- Cultural depth (Grito de Lares Sept 23)
- Vieques bio bay still warm + active
Cons
- Hurricane peak month statistical risk
- Wettest month (13 rainy days, 160mm)
- Sargassum continues
- Some small dive + tour operators close
September Events & Festivals
- **Hurricane peak month (statistically highest historical strike probability — Hurricane Maria Sep 20, 2017 Cat 4)**
- Labor Day Weekend (1st Monday — US travelers final summer)
- PR Independence Day Sept 23 (cultural significance, not federal holiday)
San Juan in September — Full Picture
September is statistically San Juan's hurricane peak month + year's lowest tourist arrival month. Hotel pricing at year's absolute lowest. The trade-off is real: 25-35% chance of hurricane disruption during any given September week + sargassum reality + daily heavy storms.
Hurricane Maria (September 20, 2017, Category 4) was the canonical PR hurricane reminder — 3,000+ deaths, 11-month power outage in worst-hit areas, infrastructure still recovering in pockets. The island is resilient but September travelers should travel with insurance + flexibility.
Labor Day Weekend (1st Monday) brings US East Coast final-summer travelers. PR Independence Day Sept 23 (Grito de Lares anniversary 1868, cultural significance) is local but not a federal holiday.
What to Wear & What to Pack
Hot + wet + hurricane risk — quick-dry, fully waterproof rain jacket, sandals for wet beach. SPF 50+. Hurricane prep dry bag.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
30°C
22°C
7.7/mo
Summer (Jun·Jul·Aug)
32°C
24°C
11.7/mo
Autumn (Sep·Oct·Nov)
Current31°C
23.3°C
12.3/mo
Winter (Dec·Jan·Feb)
28°C
21°C
8.3/mo
San Juan Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| January (Best) | 28° | 21° | 8d·75mm | 7h | 76% | 9 | Very busy | Peak |
| February (Best) | 28° | 21° | 7d·65mm | 8h | 75% | 10 | Very busy | Peak |
| March (Best) | 29° | 21° | 6d·55mm | 8h | 74% | 11 | Very busy | Peak |
| April (Best) | 30° | 22° | 7d·100mm | 8h | 75% | 11 | Busy | Shoulder |
| 31° | 23° | 10d·150mm | 8h | 76% | 12 | Moderate | Shoulder | |
| 32° | 24° | 11d·130mm | 8h | 78% | 12 | Moderate | Shoulder | |
| 32° | 24° | 12d·130mm | 8h | 78% | 12 | Busy | Peak | |
| 32° | 24° | 12d·150mm | 7h | 79% | 11 | Moderate | Shoulder | |
| 32° | 24° | 13d·160mm | 7h | 80% | 10 | Quiet | Low season | |
| 31° | 24° | 13d·165mm | 7h | 80% | 9 | Quiet | Low season | |
| November (Best) | 30° | 22° | 11d·140mm | 7h | 78% | 8 | Moderate | Shoulder |
| December (Best) | 28° | 21° | 10d·110mm | 7h | 77% | 8 | Very busy | Peak |
View Other Months
San Juan September Hotel Picks
Frequently Asked Questions
Is September a good time to visit San Juan?
San Juan in September is low. Tourist crowds are quiet and flight/hotel prices are low season.
What's the average temperature in San Juan in September?
San Juan September averages a high of 32°C and a low of 24°C.
Does it rain much in San Juan in September?
San Juan September averages 160mm of rainfall over about 13 rainy days.
What should I wear in San Juan in September?
Hot + wet + hurricane risk — quick-dry, fully waterproof rain jacket, sandals for wet beach. SPF 50+. Hurricane prep dry bag.
What time are sunrise and sunset in San Juan in September?
San Juan September sunrise is 06:20 and sunset is 18:25, with 12h 5min of daylight.
What's the air quality like in San Juan in September?
San Juan September air quality (AQI) averages 55, rated Moderate. PM2.5 averages 22μg/m³.
What activities are recommended in San Juan in September?
In September, San Juan is great for Hotel pool + spa days, Bacardí distillery (indoor), La Placita Santurce nightlife.
Is September peak season in San Juan?
San Juan September crowds are quiet and prices are low season. You can travel relatively comfortably without long queues.
Best Months to Visit San Juan
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.