Ko Samui Weather in September
Average highs run from 29°C on September 1 to 28°C on September 30, and lows from 27°C to 27°C. Normal precipitation for the month is 180 mm over about 27 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
- 29°C
- Average low
- 27°C
- Precipitation
- 180 mm
- Reanalysis high
- 31°CSep 3, 2013
- Reanalysis low
- 25°CSep 16, 2012
- Daylight
- 12 h 18 min to 12 h 03 min
- Cloud cover
- 87%
- Humidity
- 81%
- Dew point
- 24°C
- Wind
- 16.6 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 | 29°C | 27°C | 30°C 2020 | 26°C 2006 | 90% |
| Sep 2 | 29°C | 27°C | 30°C 2013 | 26°C 1999 | 90% |
| Sep 3 | 29°C | 27°C | 31°C 2013 | 26°C 1999 | 90% |
| Sep 4 | 29°C | 27°C | 30°C 2017 | 26°C 1995 | 90% |
| Sep 5 | 29°C | 27°C | 30°C 2002 | 26°C 1995 | 90% |
| Sep 6 | 29°C | 27°C | 30°C 2017 | 26°C 1999 | 90% |
| Sep 7 | 29°C | 27°C | 30°C 2015 | 26°C 1999 | 90% |
| Sep 8 | 29°C | 27°C | 30°C 2007 | 26°C 1999 | 90% |
| Sep 9 | 29°C | 27°C | 30°C 2017 | 26°C 1999 | 91% |
| Sep 10 | 29°C | 27°C | 30°C 2017 | 26°C 2000 | 91% |
| Sep 11 | 29°C | 27°C | 30°C 2017 | 26°C 2000 | 92% |
| Sep 12 | 29°C | 27°C | 30°C 2005 | 26°C 2002 | 92% |
| Sep 13 | 29°C | 27°C | 30°C 2011 | 26°C 2012 | 91% |
| Sep 14 | 29°C | 27°C | 29°C 2017 | 26°C 1994 | 90% |
| Sep 15 | 29°C | 27°C | 30°C 2013 | 26°C 2012 | 91% |
| Sep 16 | 29°C | 27°C | 30°C 2013 | 25°C 2012 | 90% |
| Sep 17 | 29°C | 27°C | 30°C 2017 | 26°C 1994 | 91% |
| Sep 18 | 29°C | 27°C | 30°C 2017 | 26°C 1994 | 91% |
| Sep 19 | 29°C | 27°C | 30°C 2017 | 26°C 1994 | 91% |
| Sep 20 | 29°C | 27°C | 30°C 2014 | 26°C 1994 | 91% |
| Sep 21 | 29°C | 27°C | 30°C 2015 | 26°C 1994 | 91% |
| Sep 22 | 29°C | 27°C | 30°C 1992 | 26°C 2007 | 91% |
| Sep 23 | 29°C | 27°C | 30°C 2015 | 26°C 2002 | 92% |
| Sep 24 | 29°C | 27°C | 30°C 2013 | 26°C 2002 | 91% |
| Sep 25 | 29°C | 27°C | 30°C 2013 | 26°C 1995 | 90% |
| Sep 26 | 28°C | 27°C | 30°C 2013 | 26°C 1994 | 90% |
| Sep 27 | 28°C | 27°C | 30°C 2013 | 26°C 1994 | 90% |
| Sep 28 | 28°C | 27°C | 29°C 2013 | 26°C 1994 | 91% |
| Sep 29 | 28°C | 27°C | 30°C 2020 | 26°C 1992 | 92% |
| Sep 30 | 28°C | 27°C | 30°C 1998 | 26°C 1994 | 92% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (GMT+7).
- September 1
- sunrise 6:11 AM, sunset 6:29 PM
- September 30
- sunrise 6:09 AM, sunset 6:12 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 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.