Weather in Koh Samui in November

How November compares

November is the 10th warmest month of the year in Koh Samui and ranks 26th of 134 destinations we compare for November - see where else is hot in November. Within Thailand it is 6th of 6 (Thailand in November). Against London's average high of 10.4°C in November, Koh Samui is 17.4°C warmer by day and 20.7°C warmer at night.

Daytime and night-time in November

The typical November day in Koh Samui peaks at 27.8°C, but that is an average: the warmest 10% of days reach 28.8°C or more. About 100% of days top 25°C and 1 in 250 pass 30°C. Nights average 25.6°C; one night in ten drops to 24.4°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest November day here reached 30.4°C (2019-11-24) and the coldest night 23.3°C (2017-11-13).

Rain in November

Wet (more than 8 rainy days): about 21 days with 1 mm or more, 281 mm in total. Year to year it varies a lot - the wettest November was 2010 with 631 mm, the driest 1994 with 88 mm. Humidity averages 82%.

Sea temperature in November

The sea averages 28.7°C - warm enough to swim (22°c+). Depending on the year it ranges from 27.8°C to 29.3°C. For the warmest sea here, come in May (30.5°C).

Sunshine and daylight

Around 3.2 hours of sunshine a day (estimated from cloud cover), 11.6 hours of daylight: the sun rises about 06:14 and sets about 17:55 local time in mid-November. Average cloud cover is 73%.

Is November a good time to visit Koh Samui?

It is a reasonable choice: hot days but expect showers. The best months for Koh Samui on our scoring are February, March, January; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Warm enough to swim, with little cooling after dark

The sea averages 28.7°C, so water temperature is not the obstacle to swimming here. Rain and conditions on the day are the bigger considerations; warm water alone does not guarantee a suitable swimming day. On land, the combination of 27.8°C daytime highs and 82% humidity can feel sticky, particularly when you are walking around at midday. Light, loose clothing makes more sense than heavy fabrics. Nights average 25.6°C, so do not expect evenings to bring much relief from the warmth. This suits travellers who like warm evenings, but may be less comfortable if you prefer cool air for sleeping.

Plan around rain rather than counting on sunny days

With about 21 rainy days, November calls for plans you can change without much fuss. That figure does not mean it rains continuously, but it is too wet a month to build a holiday around uninterrupted outdoor time. There are about 11.6 hours of daylight, yet only 3.2 hours of sunshine on average, so daylight should not be mistaken for clear skies. Pack lightweight rain protection and keep something dry to change into. For a long-haul trip from London, the catch is committing so much travel time without dependable sunshine. November makes more sense if warmth matters more to you than blue skies.