Ko Samui weather by month
Averages and records for each calendar month at Ko Samui, Thailand, from 1969 to 2025. The warmest month is May, averaging 31.1°C; the coolest is January at 27.8°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 27.8°C | 24.0°C | 36.5°C14 January 2006 | 18.6°C7 January 1999 | 48 / 57 |
| February | 28.3°C | 24.8°C | 38.9°C28 February 1995 | 17.8°C3 February 2014 | 45 / 56 |
| March | 29.3°C | 25.4°C | 39.9°C22 March 1996 | 20.4°C1 March 1989 | 48 / 56 |
| April | 30.6°C | 25.9°C | 38.0°C11 April 2016 | 21.7°C15 April 2015 | 48 / 56 |
| May | 31.1°C | 25.7°C | 37.2°C20 May 2023 | 21.3°C25 May 2016 | 48 / 56 |
| June | 31.1°C | 25.5°C | 38.0°C29 June 1982 | 20.6°C23 June 2007 | 51 / 56 |
| July | 30.7°C | 25.2°C | 38.0°C26 July 2019 | 19.9°C23 July 1990 | 50 / 56 |
| August | 30.6°C | 25.1°C | 37.2°C13 August 2024 | 18.8°C31 August 1995 | 49 / 56 |
| September | 30.2°C | 24.8°C | 39.5°C23 September 1990 | 19.4°C3 September 2005 | 49 / 55 |
| October | 29.2°C | 24.4°C | 38.9°C28 October 1990 | 20.5°C27 October 2015 | 46 / 54 |
| November | 28.3°C | 24.1°C | 39.5°C24 November 2002 | 19.6°C2 November 2015 | 47 / 55 |
| December | 27.9°C | 24.1°C | 38.5°C23 December 1990 | 18.8°C27 December 1996 | 46 / 56 |
Years shows the number behind the average high, then the number holding a record for that month. They differ because a year contributes an average only when the month has at least 25 days of readings, while a single reading is enough to set a record. The average low is withheld on the same 25-day rule and is counted separately again; it is shown as a dash where the archive cannot support it. Across the twelve months here the averages rest on 45 to 51 years each.
See what Ko Samui is doing right now
Climate at nearby stations
The closest stations with twelve months of archive of their own, nearest first.
Every figure on this page is computed from NOAA GHCN-Daily observations stored per station, per year, per month. Nothing is modelled, interpolated or estimated, and a month the archive never covered is left out rather than filled in. A station appears here only once all twelve months carry an average from at least 10 years. See how this is built.