San Juan Weather in September
September in San Juan brings very high temperatures, with highs of 30°C (86°F) and nights dropping to 26°C (79°F). Rainfall is on the higher side this month, averaging around 125 mm (4.9 in), so keep a rain jacket handy.
Rainfall in San Juan in September
You can expect rain on around 19 days based on historical patterns, with 125 mm (4.9 in) average for the month. Rain falls regularly this month and can be quite heavy when it does. Showers can be substantial, so waterproof gear is a good idea.
Temperature in San Juan in September
Temperatures in San Juan in September top out at 30°C (86°F) and drop to 26°C (79°F) overnight. It's usually most comfortable outside during the morning and later in the day. Nights are warm at 26°C (79°F). It's worth making sure your accommodation has decent ventilation or air conditioning.
Sunshine in San Juan in September
Expect a lot of sunshine this month, with about 197 hours of sun. These sunny conditions add to the overall experience.
Average water temperature in September
The water temperature is 28°C (82°F), which most people find very comfortable. A good month for swimming and water sports.September in San Juan has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Trinidad & Tobago, check out our San Juan's climate page.
San Juan Temperature in September
Min Temperature
26°C (79°F)
Max Temperature
30°C (86°F)
Water Temperature
28°C (82°F) *
Chance of Rain
63%
Precipitation
125 mm (4.9 in)
Rainy days
19 days
Humidity
84% *
Sunshine
197 hours *
Percentage Sunshine
*
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in San Juan typically stay consistent throughout September, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 24°C (75°F).
Average temperatures in September
Historical weather for San Juan in September
Browse day-by-day weather records for San Juan spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
San Juan historical weather extremes in September
Based on 35 years of weather observations (1990-2025), these are the most extreme conditions recorded in San Juan.
- On September 16, 1999, temperatures climbed to 36°C (97°F), marking the warmest September day on record.
- San Juan experienced its chilliest September day on September 7, 1991, reaching only 25°C (77°F).
- The coldest night in September in San Juan was on September 2, 2006, with a minimum of 21°C (70°F).
Best Places in Trinidad & Tobago in September
Find out more about the weather in Trinidad & Tobago and which places have the best travel conditions in this month. See all of Trinidad & Tobago in September →
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What to Wear in San Juan in September
Warm but pleasant conditions in San Juan in September. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. Expect heavy rainfall, so bring good rain protection and waterproof bags. The water temperature sits at about 28°C (82°F), making it perfect for swimming and water activities. Don't forget to pack your favorite swimwear and perhaps some snorkel gear. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.What To Do in San Juan in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Trinidad & Tobago, check out our San Juan's climate page.
Temperature Rainfall Sunshine Humidity Water Temp
See the full San Juan climate overview or explore weather in Trinidad & Tobago.
