Koh Samui, THAILAND and its best beaches
Climate - Temperatures and rainfall - South China Sea
Koh Samui: Temperatures during the day, at night, rain and bathing conditions
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Thailand : climate and when to go to Koh samui
The climate in Phuket and Koh Samui is very pleasant throughout the year, with temperatures varying between 77°F at night and 93°F during the day.
There are three seasons, the hot season from February to May, the rainy season from the end of September to November, and the "cool" season from October to January.
From February to October it average 32 to 38 degrees, but from July to September there may be some showers, but only for a few hours. The rainy season is often summed up in some "refreshing" tropical rain showers followed by the return of the sun. The climate is tropical so very wet throughout the year, but Samui always remains refreshed with a pleasant sea breeze coming from the Gulf.
January Acceptable |
February Pecfect |
March Pecfect |
April Pecfect |
May Risky |
June Acceptable |
July Acceptable |
August Acceptable |
September Acceptable |
October Avoid |
November Avoid |
December Risky |
When to go? The hottest month for the beach, lazing around and swimming is April. Check the precipitations because showers are possible but the sun returns quickly, otherwise other periods are possible. The coolest month is January, if you can not stand the heat too much. The driest month of the year is February, if you do not like the rain at all.
Click on
Phuket -
Koh Samui to display its climate.
Graphs and temperature curves with average precipitation over the year
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Precipitation, rainfall, cyclone: THAILAND
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Temperatures of bathing water around Koh Samui
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Landmarks
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No cyclone risk for this country
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South China Sea
Climate February 2025
Koh Samui sunshine in summer and winter
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The sun at its zenith, that means well perpendicular to the surface of the Earth, sending 100% of radiation and heat. Koh Samui receives in winter (january), 83% of sun power and 97% during summer time (july).
The average temperature and sunshine deviations between summer and winter are 14%. This small gap means that the temperature at sea does not really vary and that the sea remains warm enough in summer and winter. The air is also hot all year round without great thermal amplitude.

Average temperatures and rainfall for a stay in February
On the left, the averages observed every month of February on the Thailand beaches. The trends for next month are, slightly warmer daytime temperatures, a bathing water in South China Sea which takes a few degrees, more abundant rains with warmer nights.
Sunset and sunrise times for THAILAND
Local time : February 2025, Saturday 22, 05:03 PM
Sunrise time : 06:38 am, point A
Sunset time : 6:27 pm, point B
Duration of daylight : 11:49 / 24:00
Jet lag : GMT+7
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The average monthly UV index of THAILAND
What is the period of mosquitoes virulence over the year?
Weather forecast for Koh Samui
Here are the current 5-day forecasts for Ban Bang Rak / Koh Samui. Temperatures are spaced 3 hours apart for each day. The summary of the state of the sky gives the trend of the week. The sea temperature at is a monthly average. In lagoons or seashores where the bathing water is shallow, you can add some degrees.
Sunday
February 23, 2025
7 am
81.3°F
28°C
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Light rain
Humidity 76%
Sea 85°F/29°C
Sunday
February 23, 2025
10 am
80°F
27°C
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Light rain
Humidity 79%
Sea 85°F/29°C
Sunday
February 23, 2025
1 pm
80.6°F
27°C
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Light rain
Humidity 79%
Sea 85°F/29°C
Sunday
February 23, 2025
4 pm
80.4°F
27°C
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Moderate rain
Humidity 77%
Sea 85°F/29°C
Sunday
February 23, 2025
7 pm
81°F
28°C
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Light rain
Humidity 76%
Sea 85°F/29°C
Sunday
February 23, 2025
10 pm
81.1°F
28°C
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Light rain
Humidity 77%
Sea 85°F/29°C
Monday
February 24, 2025
7 am
79.6°F
27°C
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Moderate rain
Humidity 85%
Sea 85°F/29°C
Monday
February 24, 2025
10 am
79.1°F
27°C
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Moderate rain
Humidity 87%
Sea 85°F/29°C
Monday
February 24, 2025
1 pm
80°F
27°C
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Moderate rain
Humidity 84%
Sea 85°F/29°C
Monday
February 24, 2025
4 pm
80.6°F
27°C
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Moderate rain
Humidity 82%
Sea 85°F/29°C
Monday
February 24, 2025
7 pm
80.5°F
27°C
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Moderate rain
Humidity 82%
Sea 85°F/29°C
Monday
February 24, 2025
10 pm
80.5°F
27°C
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Moderate rain
Humidity 79%
Sea 85°F/29°C
Tuesday
February 25, 2025
7 am
80.3°F
27°C
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Light rain
Humidity 80%
Sea 85°F/29°C
Tuesday
February 25, 2025
10 am
79.6°F
27°C
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Moderate rain
Humidity 81%
Sea 85°F/29°C
Tuesday
February 25, 2025
1 pm
80.1°F
27°C
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Light rain
Humidity 79%
Sea 85°F/29°C
Tuesday
February 25, 2025
4 pm
80.6°F
27°C
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Light rain
Humidity 77%
Sea 85°F/29°C
Tuesday
February 25, 2025
7 pm
80°F
27°C
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Light rain
Humidity 77%
Sea 85°F/29°C
Tuesday
February 25, 2025
10 pm
80.4°F
27°C
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Light rain
Humidity 75%
Sea 85°F/29°C
Wednesday
February 26, 2025
7 am
80.6°F
27°C
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Light rain
Humidity 76%
Sea 85°F/29°C
Wednesday
February 26, 2025
10 am
80°F
27°C
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Light rain
Humidity 80%
Sea 85°F/29°C
Wednesday
February 26, 2025
1 pm
80.8°F
28°C
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Light rain
Humidity 78%
Sea 85°F/29°C
Wednesday
February 26, 2025
4 pm
80.4°F
27°C
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Light rain
Humidity 78%
Sea 85°F/29°C
Wednesday
February 26, 2025
7 pm
80.7°F
28°C
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Light rain
Humidity 74%
Sea 85°F/29°C
Wednesday
February 26, 2025
10 pm
79.8°F
27°C
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Light rain
Humidity 79%
Sea 85°F/29°C
Thrusday
February 27, 2025
7 am
80.2°F
27°C
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Moderate rain
Humidity 80%
Sea 85°F/29°C
Thrusday
February 27, 2025
10 am
80.6°F
27°C
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Light rain
Humidity 81%
Sea 85°F/29°C
Weather uncertainties 2025 to go to Koh Samui ?
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When traveling in the tropics as a seaside, rain is not welcome. If you see this indicator, with possible storms, that does not mean that it will rain all day long. When we observe the local rainfall, it is either really zero or very weak. Meteorologists prefer to be pessimistic. So observe below, the skies photographed during a week announced stormy in Asia. It did not rain once. I invite you to integrate this parameter before going to Koh Samui for a good trip to the sun!
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