Saint Thomas weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: December – April
What is the weather like in Saint Thomas in September?
In September, Saint Thomas is hot: daytime highs average 28 °C, and even at night it stays warm at around 27 °C. The sea averages 29.1 °C – almost as warm as a bath. The sun shines for around 8 hours a day. It is the rainy season: rain falls on about 18 days, totalling 135 mm. The air is often humid and muggy. All in all, September is a so-so month for a holiday in Saint Thomas.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 61 | 59 | 61 |
| Day | 28° | 28° | 28° |
| Night | 27° | 27° | 26° |
| Sea | 29° | 29° | 29° |
| Sun | 9 h | 8 h | 8 h |
| Rain days | 18 | 18 | 19 |
More details for September
- Daylight
- 12 h 16 min06:07 – 18:23
- UV index
- 12 · extremeclear sky, noon (estimate)All months
- Muggy days
- 30 daysdew point 18 °C or moreAll months
- Wind
- 26 km/haverage daily peakAll months
- Cloud cover
- 58 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Time zone
- UTC−4America/St_Thomas
How the score comes together
- Temperatureweight 50 %84 %
- Sunshineweight 20 %85 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Saint Thomas in September: quick answers
Is Saint Thomas hot in September?
Yes. In September, Saint Thomas is hot: daytime highs average 28 °C and nights stay around 27 °C.
Can you swim in Saint Thomas in September?
Yes. In September the sea averages 29.1 °C – almost as warm as a bath.
Does it rain much in Saint Thomas in September?
It rains often – on about 18 days, adding up to 135 mm.
Saint Thomas month by month
The whole year in Saint ThomasAll destinations: U.S. Virgin IslandsCaribbean weather in SeptemberWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences