Koh Samui weather in January 2026

Expect 29°C daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Koh Samui in January based on long-term weather averages. There is usually 10 days with some rainfall and 123 mm of average monthly rainfall in January.

  • 29°C maximum daytime temperature in January in Koh Samui29
    29°C max day temperature
  • 7 hours of sunshine per day
  • 10 days with some rainfall in January in Koh Samui10
    10 days with some rainfall
  • 22°C minimum night-time temperature in January in Koh Samui22
    22°C min night temperature
  • 12 hours of daylight per day in January in Koh Samui12
    12 hours of daylight per day
  • High heat & humidity in January in Koh SamuiH
    High heat & humidity
  • 123 mm monthly rainfall in January in Koh Samui123
    123 mm of monthly rainfall
  • UV (maximum) index 11 (Extreme) in January in Koh Samui11
    11 (Extreme) UV index
  • 28°C sea temperature in January in Koh Samui28
    28°C sea temperature

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The January weather guide for Thailand (Koh Samui) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm)  |  Imperial (°F / inches)

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How hot is it in Koh Samui in January?

Daytime temperatures usually reach 29°C in Koh Samui in January with high heat and humidity, falling to 22°C at night.

How sunny is it in Koh Samui in January?

There are normally 7 hours of bright sunshine each day in Koh Samui in January - that's 64% of daylight hours.

How warm is the sea around Koh Samui in January?

The average sea temperature around Koh Samui in January is 28°C.

Does it rain in Koh Samui in January?

There are usually 10 days with some rain in Koh Samui in January and the average monthly rainfall is 123mm.

Koh Samui January sunrise & sunset times

Browse the sunrise and sunset times for Koh Samui in January 2026. Select a month to view Koh Samui sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Thursday, 1st January 2026 06:36 18:11
Friday, 16th January 2026 06:40 18:18
Saturday, 31st January 2026 06:42 18:25

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