Annual average weather for Ko Samui, Thailand

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Annual Average Weather for Ko Samui, Thailand

The annual average maximum daily temperature is 31.5°C (88.6°F) which is very hot and perfect for sunbathing on clear days. The annual average water temperature is typically 28.9°C (84.1°F) which is very warm and ideal for relaxing and swimming for the whole day. Annually there are on average 14.5 days of rain per month and 6.1 hours of sun per day.

When is the best time to visit Ko Samui?

The best months to visit Ko Samui are January, February, March, April, for the best beach weather, the most sunshine and optimal sunbathing and swimming conditions with the least chance of rain.

The sea is best for swimming between December and October when the sea temperature is above the average 29°C (84°F) which is very warm and ideal for relaxing and swimming for the whole day.

Can you sunbathe in Ko Samui year round?

Yes, you can sunbathe in Ko Samui all year round.

The coolest month in Ko Samui is January when the average maximum temperature is 30°C (86°F), average temperature is 28°C (82°F) and average minimum temperature is 25°C (78°F).

More info about the annual temperatures and sunshine.

Can you swim in Ko Samui year round?

Yes, you can swim in Ko Samui all year round.

The warmest sea water temperatures in Ko Samui are found in June when they peak at 30°C (86°F) and lowest in December when they dip to 27°C (80°F).

The sea is excellent for swimming all year round as the water temperature is very warm and ideal for relaxing and swimming for the whole day.

More info about the annual sea temperatures

When is the hottest month in Ko Samui?

The hottest month in Ko Samui is May when the average maximum temperature is very hot and perfect for sunbathing on clear days 33°C (91°F), average temperature is 30°C (86°F) and average minimum temperature is 27°C (81°F).

More info about the annual temperatures and sunshine.

When is the coldest month in Ko Samui?

The coolest month in Ko Samui is January when the average maximum temperature is 30°C (86°F), average temperature is 28°C (82°F) and average minimum temperature is 25°C (78°F).

More info about the annual temperatures and sunshine

When is the sunniest month in Ko Samui?

The sunniest days in Ko Samui are in July which has the most hours of sunshine per day. In July the sunshine percentage is 57.1% making it quite sunny but with occasional periods of cloudy and overcast skies. There are 7.2 hours of sunshine per day.

More info about the annual sunshine.

When is the least sunny month in Ko Samui?

January has the least sunshine. In January the sunshine percentage is 42.8% making it quite sunny but with regular periods of cloudy and overcast skies. There are 5.0 hours of sunshine per day.

More info about the annual sunshine.

When is the driest month in Ko Samui?

The driest month in Ko Samui is February with 1.3cm (0.5inches) of rain and the least days of rain with 3 days with some rain, a very dry time to visit the beach.

More info about the annual rainfall

When is the wettest month in Ko Samui?

The wettest month in Ko Samui is November with 26.5cm (10.4inches) of rain and October has the most days of rain with 23 days with some rain, a very wet time to visit the beach.

More info about the annual rainfall.

When is the sea the coldest in Ko Samui?

The coldest sea water temperatures in Ko Samui are found in December when they dip to 27°C (80°F) which is very warm and ideal for relaxing and swimming for the whole day.

More info about the annual sea temperatures.

When is the sea the warmest in Ko Samui?

The warmest sea water temperatures in Ko Samui are found in June when they peak at 30°C (86°F) which is very warm and ideal for relaxing and swimming for the whole day.

More info about the annual sea temperatures.

When is the most humid month in Ko Samui?

The most humid month in Ko Samui is April with a dew point (an indicator of humidity) of 26°C (79°F) which is very uncomfortable and fairly oppressive unless you are on a beach. At night you would most likely require airconditioning.

More info about the annual humidity.

When is the least humid month in Ko Samui?

The least humid month in Ko Samui is January with a dew point of 24°C (75°F) which is very uncomfortable and fairly oppressive unless you are on a beach. At night you would most likely require airconditioning.

More info about the annual humidity.

When is the windiest month in Ko Samui?

The most windy month in Ko Samui is July when the average maximum windspeed is 25KM/H (16MPH) and the average wind speed is 11KM/H (7MPH).

More info about the annual wind conditions.

Annual Temperature for Ko Samui

The hottest month in Ko Samui is May when the average maximum temperature is 33°C (91°F), average temperature is 30°C (86°F) and average minimum temperature is 27°C (81°F).

The coolest month in Ko Samui is January when the average maximum temperature is 30°C (30°F), average temperature is 28°C (82°F) and average minimum temperature is 25°C (78°F).

Annual Sunshine for Ko Samui

The longest days in Ko Samui are in June, with an average of 12.7 hours of daylight per day. January has the shortest days with an average of 11.6 hours of daylight per day.

The sunniest days in Ko Samui are in July which has the most hours of sunshine per day. The sunshine percentage is 57.1% making it quite sunny but with occasional periods of cloudy and overcast skies. There are 7.2 hours of sunshine per day.

January has the least sunshine. The sunshine percentage is 42.8% making it quite sunny but with regular periods of cloudy and overcast skies. There are 5.0 hours of sunshine per day.

The ultraviolet index is the highest in March when it reaches 14.8 and lowest in December when it reaches 10.5.

An ultraviolet index reading above 11 indicates an extreme risk of harm from unprotected sun exposure. Unprotected skin risks burning in less than 10 minutes. Take all precautions because unprotected skin and eyes can burn in minutes. Tanning will be safest before 10am and after 4pm but only with a good application of sun screen. For those with sensitive skin stay in the shade and wear protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days. Watch out for relections from water that may increase ultraviolet exposure.

Annual Sea Temperature for Ko Samui

The warmest sea water temperatures in Ko Samui are found in June when they peak at 30°C (86°F) and lowest in December when they dip to 27°C (80°F).

The sea is excellent for swimming all year round as the water temperature is very warm and ideal for relaxing and swimming for the whole day.

Annual Rainfall for Ko Samui

The wettest month in Ko Samui is November with 26.5cm (10.4inches) of rain and October has the most days of rain with 23 days with some rain, a very wet time to visit the beach.

The driest month in Ko Samui is February with 1.3cm (0.5inches) of rain and the least days of rain with 3 days with some rain, a very dry time to visit the beach.

Annual Humidity for Ko Samui

The most humid month in Ko Samui is April with a dew point (an indicator of humidity) of 26°C (79°F) which is very uncomfortable and fairly oppressive unless you are on a beach. At night you would most likely require airconditioning.

The least humid month in Ko Samui is January with a dew point of 24°C (75°F) which is very uncomfortable and fairly oppressive unless you are on a beach. At night you would most likely require airconditioning.

Annual Wind Speed for Ko Samui

The most windy month in Ko Samui is July when the average maximum windspeed is 25KM/H (16MPH) and the average wind speed is 11KM/H (7MPH).

The least windy month in Ko Samui is April when the average maximum windspeed is 22KM/H (13MPH) and the average wind speed is 11KM/H (7MPH).

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