St. Thomas Weather in September
Average highs run from 26°C on September 1 to 19°C on September 30, and lows from 15°C to 9°C. Normal precipitation for the month is 69 mm over about 12 wet days.
September day by day
The normal high and low for each date, in °C.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
September at a glance
- Average high
- 23°C
- Average low
- 12°C
- Precipitation
- 69 mm
- Reanalysis high
- 35°CSep 8, 2002
- Reanalysis low
- -1°CSep 30, 1993
- Daylight
- 13 h 09 min to 11 h 47 min
- Cloud cover
- 56%
- Humidity
- 71%
- Dew point
- 11°C
- Wind
- 15.8 km/h
Every day of the month
A wet day has at least 1 mm of precipitation in the reanalysis.
| Date | Normal high | Normal low | Reanalysis high | Reanalysis low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 26°C | 15°C | 32°C 2010 | 7°C 2017 | 35% |
| Sep 2 | 26°C | 15°C | 33°C 2011 | 8°C 1994 | 38% |
| Sep 3 | 26°C | 15°C | 33°C 2008 | 7°C 1994 | 38% |
| Sep 4 | 26°C | 14°C | 31°C 2018 | 7°C 1997 | 38% |
| Sep 5 | 26°C | 14°C | 32°C 2018 | 6°C 2000 | 37% |
| Sep 6 | 25°C | 14°C | 33°C 2007 | 7°C 2013 | 37% |
| Sep 7 | 25°C | 14°C | 32°C 2002 | 9°C 1993 | 39% |
| Sep 8 | 25°C | 14°C | 35°C 2002 | 7°C 1995 | 40% |
| Sep 9 | 25°C | 14°C | 34°C 2002 | 6°C 2017 | 40% |
| Sep 10 | 25°C | 13°C | 33°C 2002 | 6°C 1995 | 40% |
| Sep 11 | 24°C | 13°C | 31°C 2013 | 6°C 1992 | 39% |
| Sep 12 | 24°C | 13°C | 32°C 2005 | 5°C 1992 | 40% |
| Sep 13 | 24°C | 13°C | 30°C 2005 | 6°C 2013 | 41% |
| Sep 14 | 24°C | 13°C | 29°C 2018 | 4°C 2013 | 42% |
| Sep 15 | 23°C | 12°C | 31°C 1991 | 6°C 1995 | 42% |
| Sep 16 | 23°C | 12°C | 30°C 1991 | 6°C 2013 | 42% |
| Sep 17 | 23°C | 12°C | 28°C 2003 | 5°C 2013 | 41% |
| Sep 18 | 23°C | 12°C | 28°C 2018 | 5°C 1995 | 40% |
| Sep 19 | 23°C | 12°C | 29°C 2007 | 3°C 2020 | 41% |
| Sep 20 | 22°C | 11°C | 29°C 2016 | 5°C 1991 | 42% |
| Sep 21 | 22°C | 11°C | 29°C 2018 | 5°C 1999 | 43% |
| Sep 22 | 22°C | 11°C | 30°C 2016 | 3°C 1999 | 42% |
| Sep 23 | 22°C | 11°C | 32°C 2017 | 3°C 1995 | 43% |
| Sep 24 | 21°C | 10°C | 31°C 2017 | 3°C 1997 | 44% |
| Sep 25 | 21°C | 10°C | 31°C 2017 | 4°C 2001 | 45% |
| Sep 26 | 21°C | 10°C | 30°C 1998 | 3°C 2001 | 47% |
| Sep 27 | 20°C | 10°C | 28°C 1999 | 3°C 1991 | 49% |
| Sep 28 | 20°C | 10°C | 27°C 1999 | 1°C 2000 | 48% |
| Sep 29 | 20°C | 9°C | 25°C 1995 | 3°C 1993 | 47% |
| Sep 30 | 19°C | 9°C | 26°C 2002 | -1°C 1993 | 46% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (EDT).
- September 1
- sunrise 6:50 AM, sunset 7:59 PM
- September 30
- sunrise 7:21 AM, sunset 7:08 PM
Other months
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.