September · Puerto Rico
Best time to visit San Juan in September Weather, crowds & prices
Weather in San Juan in September
Average temperature 29°C, 151 mm of rain, about 26 days with 6+ hours of sunshine and 79% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
7.7/10
Ranked #9 of 12 months
- Avg temp
- 29°C
- Rainfall
- 151 mm
- Humidity
- 79%
- Days with 6h+ sun
- 26
- Crowd Density
- Quiet / Uncrowded
- Average Expenses
- $$ · Moderate Cost ($$)
September in San Juan scores 7.7/10 for beach and coastal travel - ranked #9 of 12. Expect around 29°C, 151 mm of rain, and roughly 26 days with 6+ hours of sunshine this month.
Old San Juan's blue cobbles, fortresses and salsa bars face the Atlantic in Puerto Rico's capital.
September in San Juan: strong conditions, 9th of 12
Days in September average 29°C (84°F) and humidity near 79% — front-load outdoor plans before the heat builds and treat the middle of the day as indoor time.
151 mm of rain makes this a wet month here, though with about 26 days with 6+ hours of sunshine there is still bright weather between the fronts.
That is 7.7/10 on the same scale — 9th of 12 months, versus 9.4/10 for the best month here.
Pack the lightest breathable clothing you own, a hat, and more water than feels necessary, a proper rain shell rather than an umbrella.
Expect mid-season pricing, and crowds are light for this destination.
If your dates are flexible, March is materially better in San Juan — 1.7 points higher on the same scale.
Frequently asked
- What is the weather like in San Juan in September?
- In September, San Juan averages 29°C, 151 mm of rain, and about 26 days with 6+ hours of sunshine. Its climate-comfort score is 7.7/10.
- Is September a good time to visit San Juan?
- September earns a 7.7/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in San Juan in September?
- Expect about 151 mm of rain in September. Average humidity is 79% and there are about 26 days with 6+ hours of sunshine.
Curated in San Juan
Tickets & experiences
Things to do in San Juan
San Juan, Puerto Rico. Live activities and tours from GetYourGuide, matched to this destination.