Last updated: August 27, 2025
In December, Ko Samui, Thailand experiences warm and humid weather, with average temperatures hovering around 27°C (80°F). Daily highs can reach a comfortable 29°C (84°F), while nights cool down to a minimum of 24°C (76°F). This month marks a period of notable rainfall, with 207 mm (8.1 in) of precipitation spread across 17 days, contributing to a lush and vibrant landscape. With humidity levels around 83%, visitors can expect a tropical climate perfect for exploring the island's natural beauty, albeit with occasional rain showers to keep the atmosphere refreshing.
In December, Ko Samui offers a delightful escape from the chill of winter elsewhere, with temperatures that range from a minimum of 24°C (76°F) to a maximum of 29°C (84°F). The average temperature remains consistently pleasant at 27°C (80°F), reflecting a tropical ambiance that makes this island irresistible during the holiday season. As the year winds down, visitors can expect slightly cooler nights compared to the warmer months, while daytime temperatures remain invitingly warm. This month marks a smooth transition toward the peak tourist season, as visitors flock to soak in the sun and embrace the island's vibrant culture, all set against a backdrop of beautiful beaches and clear skies.
In December, Ko Samui experiences a significant shift in precipitation, with a total rainfall of 207 mm (8.1 in) spread over 17 days. This marks a notable decrease compared to the intense rains of November, which recorded a hefty 336 mm (13.2 in) over 24 days. As the island transitions towards the drier months, December brings a mix of rain and sunshine, contributing to lush landscapes while still offering plenty of opportunities for outdoor activities. Although sporadic showers are common, the rainfall lessens in frequency, hinting at the approach of a sunnier January. Overall, December’s weather provides a perfect balance, making it an appealing destination for visitors seeking both relaxation and natural beauty.
In December, Ko Samui experiences a humidity level of 83%, marking a slight decrease from the peak levels seen in the preceding months of August (88%) and September (87%). This gradual decline is indicative of the region's transition from the heavy rains of the monsoon season into a relatively drier period. The fluctuation across the year shows that the humidity remains consistently high, particularly during the mid-year months, where it frequently hovers around the 85% to 88% range. As the year wraps up, the December humidity offers a reminder of the tropical climate, balancing warmth with a comfortable level of moisture that still enchants visitors drawn to the island's beautiful landscapes.
In December, Ko Samui experiences a UV Index of 11, categorizing it as extreme and maintaining a consistent burn time of just 10 minutes for unprotected skin. As the year draws to a close, this level mirrors that of November, where the UV Index also stands at 11. Throughout the months leading up to December, the island has seen an impressive peak in UV radiation, hitting its highest in March and April at 15. This trend reflects a generally stable yet intense exposure level that characterizes Ko Samui's tropical climate. Visitors should always remain vigilant and take protective measures, especially during the sunniest hours. For more detailed insights on UV levels throughout the year, explore Ko Samui UV Index.
UV Risk Categories
As December unfolds in Ko Samui, Thailand, travelers can bask in an impressive 302 hours of sunshine, setting the stage for a warm holiday escape. This month shines brightly, following a robust streak of sunlight that peaks in March with 346 hours. While December remains radiant, it reflects a slight dip from the vibrant spring but still outshines the gloom of other months. The consistent sunshine throughout the year, particularly from January to April, reveals a tropical paradise where sunny days are the norm, making Ko Samui an ideal destination for those seeking sun-soaked adventures during the festive season.
When considering the likelihood of sunny weather in December in Ko Samui, Thailand, you'll find a refreshing change as the year comes to a close. With a 39% chance of sunshine, December marks a notable upswing compared to the previous months, particularly the stark lows of just 8% in November and the dismal 9% in August. This trend suggests the start of a brighter season, as the island begins to transition into a more favorable climate for beach activities and outdoor adventures. While still tempered by some rain, this increased probability of sunlight makes December an attractive time for visitors seeking to soak up the tropical ambiance that Ko Samui is known for.
In Ko Samui, Thailand, the daylight duration showcases a delightful pattern throughout the year. Starting from January, the island enjoys around 11 hours of sunlight, a trend that continues into February. As the year progresses into March, daylight peaks at 12 hours, maintaining this generous amount through April, May, and the summer months. June to September hold steady at 12 hours, offering ample time for beach activities and exploration. However, as October rolls in, a gentle decline begins, with daylight dipping back to 11 hours in October and maintaining that duration through November and December. This rhythmic fluctuation between 11 to 12 hours creates an inviting atmosphere year-round, ideal for both relaxation and adventure.
As December arrives in Ko Samui, the island experiences a noticeable uptick in wind speed, averaging 5.4 m/s (12 mph). This marks a return to the brisker breezes reminiscent of the summer months, notably higher than the calmer conditions seen in April and May. The gentle yet invigorating winds of December create an ideal atmosphere for beachgoers and water sports enthusiasts alike. As the year winds down, the consistent winds serve to enhance the tropical charm of the island, making it an enticing destination during this festive season. With the winds picking up at the end of the year, visitors can enjoy both the beauty of the landscape and the thrill of outdoor activities, all under the warm Thai sun.
Weather in Ko Samui varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Ko Samui, focusing on differences in temperature, rainfall, humidity, and UV levels.
In December, the weather typically features a warm range of temperatures, with lows around 24°C (76°F) and averages reaching 27°C (80°F), peaking at 29°C (84°F). The month sees substantial precipitation, with 207 mm (8.1 in) spread over 17 days, contributing to a high humidity level of 83%. In contrast, January maintains a similar temperature profile, with minimums remaining at 24°C (76°F) and an average of 27°C (80°F), but the maximum temperature slightly lowers to 28°C (83°F). Notably, January experiences less rainfall, totaling 144 mm (5.7 in) over just 13 days, and a drop in humidity to 72%. This shift results in a drier and somewhat more comfortable climate during January. For more detailed insights, visit Ko Samui weather in January.
In December, the weather typically features minimum temperatures around 24°C (76°F) and an average of 27°C (80°F), with maximum temperatures peaking at 29°C (84°F). However, this month is marked by significant precipitation, recording 207 mm (8.1 in) over 17 rainy days and high humidity levels at 83%. In contrast, February experiences slightly warmer minimum temperatures of 25°C (77°F) and an overall average of 27°C (81°F), but with lower maximum temperatures of 28°C (83°F). This month sees a drastic reduction in precipitation, with only 39 mm (1.5 in) accumulating over just 8 days and a more comfortable humidity level of 68%. For more detailed information on February's weather, you can check out Ko Samui weather in February.
In December, the weather is characterized by slightly cooler temperatures, ranging from a minimum of 24°C (76°F) to a maximum of 29°C (84°F), with an average temperature of 27°C (80°F). This month experiences significant rainfall, totaling 207 mm (8.1 in) over 17 days, and high humidity at 83%. In contrast, March sees warmer temperatures, with a minimum of 25°C (78°F) and a maximum of 30°C (86°F), averaging 28°C (82°F). Additionally, March is much drier, receiving only 38 mm (1.5 in) of precipitation over just 7 days, and the humidity drops to 68%. For more details, check out Ko Samui weather in March.
In December, temperatures are slightly cooler, with a minimum of 24°C (76°F) and an average around 27°C (80°F), peaking at 29°C (84°F). The month sees considerable rainfall, totaling 207 mm (8.1 in) over about 17 days, contributing to a high humidity level of 83%. In contrast, April experiences warmer temperatures, with a minimum of 25°C (77°F) and an average of 28°C (83°F), reaching a maximum of 31°C (88°F). While April also sees some rainfall, it is significantly less, with 144 mm (5.7 in) over 15 days and a lower humidity of 69%. For more detailed information, you can check Ko Samui weather in April.
In December, the weather is characterized by slightly cooler temperatures, with averages around 27°C (80°F) and a maximum of 29°C (84°F). This month sees significant rainfall, totaling 207 mm (8.1 in) over 17 days, resulting in a high humidity level of 83%. In contrast, May experiences warmer conditions, with temperatures ranging from a minimum of 26°C (79°F) to a maximum of 32°C (89°F) and average temperatures of 28°C (84°F). Although May has less precipitation at 126 mm (5.0 in) spread over 22 days, it still retains a notable humidity of 77%. For more detailed information, you can explore the Ko Samui weather in May.
In December, the weather tends to be slightly cooler with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 29°C (84°F). However, it is also more humid, with humidity levels reaching up to 83% and significant rainfall measuring 207 mm (8.1 in) over 17 days. In contrast, June's temperatures are a bit warmer, with averages around 26°C (79°F) to 32°C (89°F), but it experiences less rain, totaling 96 mm (3.8 in) over 18 days and a slightly higher humidity level of 86%. For more detailed information about the weather in June, visit Ko Samui weather in June.
In December, the weather is slightly milder compared to July, with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 29°C (84°F). December also experiences significantly higher precipitation, totaling 207 mm (8.1 in) over 17 days, which contributes to the humidity level of 83%. In contrast, July sees warmer temperatures, reaching an average high of 31°C (88°F) with slightly lower precipitation of 79 mm (3.1 in) over the same number of rainy days, and a humidity level of 86%. For more details on the weather in July, visit Ko Samui weather in July.
In December, the weather tends to be slightly cooler with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 29°C (84°F). The month experiences significant rainfall, accumulating 207 mm (8.1 in) over 17 days, coupled with a humidity level of 83%. In contrast, August is warmer, with average temperatures peaking at 31°C (89°F) and lows of 26°C (79°F). While it also sees rain, the total precipitation is considerably less at 80 mm (3.1 in) over 18 days, and humidity is slightly higher at 88%. For more detailed information about the weather in August, you can check out Ko Samui weather in August.
In comparing the weather between December and September, December tends to be slightly cooler with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 29°C (84°F). In contrast, September features a warmer range, with temperatures varying from 26°C (78°F) to 30°C (86°F). Precipitation levels are higher in December, totaling 207 mm (8.1 in) over 17 days, compared to September’s 151 mm (5.9 in) over 21 days. Additionally, December has a humidity level of 83%, which is slightly lower than September's 87%. For a more in-depth understanding, you can check Ko Samui weather in September.
In comparing the weather between October and December, both months exhibit warm temperatures, with December having a slightly lower minimum temperature of 24°C (76°F) compared to October’s 25°C (77°F). The average temperatures remain similar, hovering around 27°C (81°F) in both months, but October can reach a higher maximum of 30°C (85°F) versus December's 29°C (84°F). Precipitation levels also differ, with October receiving 241 mm (9.5 in) over 28 days, while December has 207 mm (8.1 in) spread across 17 days. Humidity remains relatively high in both months, with December at 83% and October at 86%. For more detailed information, you can check Ko Samui weather in October.
In comparing the weather between November and December, December tends to be slightly warmer with a minimum temperature of 24°C (76°F) compared to November's 25°C (77°F). Both months share an average maximum temperature of around 29°C (84°F in December and 85°F in November). However, November experiences significantly higher precipitation, with 336 mm (13.2 in) over 24 days, whereas December sees only 207 mm (8.1 in) over 17 days, making it a drier month overall. Additionally, humidity levels are a bit lower in December at 83% compared to November's 87%. For more detailed insights, you can visit Ko Samui weather in November.
As December settles in on Ko Samui, visitors can expect a delightful shift in weather compared to the rest of the year. With temperatures averaging a comfortable 27°C, the island is warm yet not overwhelmingly hot, making it perfect for outdoor adventures and beach lounging. However, December also brings an uptick in rainfall, with about 17 days of precipitation adding to the lush greenery of the island. The high humidity at 83% contributes to a tropical feel, ensuring that even the occasional showers can't dampen the spirit of island life. For those planning a trip, be sure to explore more about the weather patterns by checking out Ko Samui Climate.