Koh Samui weather live forecast

Today's maximum temperature in Koh Samui is expected to be 33°C. Select a day from the live weather forecast for Koh Samui, Thailand for more weather parameters.

5-day weather forecast updated at 04:01 on Sunday 21st September 2025 GMT

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The 5-day weather forecast for Thailand (Koh Samui) is provided by the Swiss meteorological agency, meteoblue. Find out more about our data sources.

Koh Samui weather forecast by day

Below are the detailed weather forecasts for Koh Samui for the next 5 days.

Koh Samui weather for Sunday 21st September 2025

Expect scattered clouds in Koh Samui, Thailand with a maximum temperature of 33°C, high levels of heat & humidity, maximum UV of 11+ (Extreme) and 9 hours of bright sunshine. There are 0 mm of rainfall expected and a gentle breeze of 13 kph from the south-west.

  • 33°C maximum temperature33
    °C maximum temperature
  • 27°C minimum temperature27
    °C minimum temperature
  • Scattered clouds
    scattered clouds
  • 9 hours of bright sunshine9
    hours of sunshine
  • UV (maximum) index 11+ (Extreme)11
    UV index (Extreme)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Gentle breeze of 13 kph from the South-West13
    kph wind from SW

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Koh Samui weather for Monday 22nd September 2025

Expect scattered clouds in Koh Samui, Thailand with a maximum temperature of 32°C, moderate levels of heat & humidity, maximum UV of 11+ (Extreme) and 10 hours of bright sunshine. There are 0 mm of rainfall expected and a light breeze of 12 kph from the west.

  • 32°C maximum temperature32
    °C maximum temperature
  • 28°C minimum temperature28
    °C minimum temperature
  • Scattered clouds
    scattered clouds
  • 10 hours of bright sunshine10
    hours of sunshine
  • UV (maximum) index 11+ (Extreme)11
    UV index (Extreme)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • Moderate heat & humidityM
    moderate heat & humidity
  • Light breeze of 12 kph from the West12
    kph wind from W

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Koh Samui weather for Tuesday 23rd September 2025

Expect scattered clouds in Koh Samui, Thailand with a maximum temperature of 33°C, high levels of heat & humidity, maximum UV of 11 (Extreme) and 10 hours of bright sunshine. There are 0 mm of rainfall expected and a gentle breeze of 15 kph from the west.

  • 33°C maximum temperature33
    °C maximum temperature
  • 28°C minimum temperature28
    °C minimum temperature
  • Scattered clouds
    scattered clouds
  • 10 hours of bright sunshine10
    hours of sunshine
  • UV (maximum) index 11 (Extreme)11
    UV index (Extreme)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Gentle breeze of 15 kph from the West15
    kph wind from W

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Koh Samui weather for Wednesday 24th September 2025

Expect isolated thunderstorms in Koh Samui, Thailand with a maximum temperature of 32°C, high levels of heat & humidity, maximum UV of 11 (Extreme) and 8 hours of bright sunshine. There are 2-5 mm of rainfall expected with 47% chance of some rain and a gentle breeze of 17 kph from the west.

  • 32°C maximum temperature32
    °C maximum temperature
  • 28°C minimum temperature28
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 8 hours of bright sunshine8
    hours of sunshine
  • UV (maximum) index 11 (Extreme)11
    UV index (Extreme)
  • 47% chance of some rain47
    % chance of some rain
  • 2-5 mm of rainfall expected<5
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Gentle breeze of 17 kph from the West17
    kph wind from W

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Koh Samui weather for Thursday 25th September 2025

Expect broken clouds in Koh Samui, Thailand with a maximum temperature of 32°C, high levels of heat & humidity, maximum UV of 9 (Very High) and 6 hours of bright sunshine. There are 0 mm of rainfall expected and a gentle breeze of 17 kph from the west.

  • 32°C maximum temperature32
    °C maximum temperature
  • 28°C minimum temperature28
    °C minimum temperature
  • Broken clouds
    broken clouds
  • 6 hours of bright sunshine6
    hours of sunshine
  • UV (maximum) index 9 (Very High)9
    UV index (Very High)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Gentle breeze of 17 kph from the West17
    kph wind from W

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

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