December weather forecast
Ko Samui, Thailand

December in Ko Samui, Thailand, explains a significant decrease in rainfall to 210mm (8.27") from November. The dense monsoon clouds start to clear up spelling out a shift towards drier months. Temperatures remain steady, promising comfortable holiday weather. The diminishing rains and amiable climate make this month popular among tourists. The ushering in the new year at cozy beaches under the tropical sun is a common sight.

Temperature

The beginning of December in Ko Samui reveals an average high-temperature of a tropical 32°C (89.6°F), showing minimal deviation from the previous month. Throughout December, an average nighttime temperature of 23.9°C (75°F) is experienced in Ko Samui.

Heat index

December's average heat index is computed to be a blazing hot 45°C (113°F). Stay vigilant: Heat cramps along with heat exhaustion are expected. Heatstroke may follow prolonged exertion.
Realize that the values for the heat index are set for shaded places and light winds. The heat index can potentially augment by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'real feel' or 'apparent temperature', offers an insight into how hot it feels when we factor in moisture content. The experience of temperature can be subjective, varying based on the individual's activity and heat perception, influenced by factors like wind, attire, and metabolic variations. With direct sunlight, be aware that it might enhance the heat sensation, raising the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Children regularly disregard the necessity to rest and replenish fluids. Thirst is a late symptom of dehydration - thus, maintaining hydration, particularly during long-lasting physical activities, is essential.
For the human body, perspiration is the go-to method to regulate temperature, using sweat's evaporation to dissipate warmth. When relative humidity is heightened, it slows the rate of evaporation, thereby decreasing the body's ability to shed heat and creating a sensation of overheating. Excessive heat that's not properly managed leads to increased body temperatures and resultant health issues.

Humidity

In Ko Samui, the average relative humidity in December is 82%.

Rainfall

In Ko Samui, in December, during 15 rainfall days, 210mm (8.27") of precipitation is typically accumulated. In Ko Samui, during the entire year, the rain falls for 160 days and collects up to 1960mm (77.17") of precipitation.

Sea temperature

In December, the average sea temperature in Ko Samui, Thailand, is 28.2°C (82.8°F).
Note: For activities in the water such as swimming or diving, temperatures from 25°C (77°F) to 29°C (84.2°F) are considered optimal for prolonged enjoyment without discomfort.

Daylight

December has the shortest days of the year, with an average of 11h and 36min of daylight.
On the first day of December in Ko Samui, sunrise is at 06:20 and sunset at 17:57. On the last day of the month, sunrise is at 06:35 and sunset at 18:10 +07.

Sunshine

May through December, with an average of 6h of sunshine, are months with the least sunshine.

UV index

The month with the lowest UV index is December, with an average maximum UV index of 10. A UV Index reading of 8 to 10 represents a very high health vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: A maximum daily UV index of 10 during December morphs into the following directions:
Prioritize protection; rapid damage can occur to unprotected eyes and skin. Make an effort to avoid direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation, and note that objects like parasols or canopies might not offer full sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Directly after swimming or an outdoor workout, generously apply and reapply a broad-spectrum SPF 30+ sunscreen. Caution! Sand and water reflections can notably increase the UV radiation intensity.