January Weather in Ko Samui, Thailand

Last updated: August 27, 2025

January in Ko Samui, Thailand, offers a tropical climate ideal for visitors seeking warmth and relaxation. With maximum temperatures reaching 28°C (83°F) and an average of 27°C (80°F), the weather remains comfortably warm. Expect daytime highs to complement the minimum nighttime lows of 24°C (76°F). However, be prepared for rain, as January sees about 144 mm (5.7 in) of precipitation across an average of 13 rainy days, contributing to the island's lush greenery. With a humidity level of 72%, the air feels pleasantly tropical, making it a perfect time for beach lovers and adventurers alike to explore the natural beauty of this stunning destination.

January Temperature in Ko Samui

In January, Ko Samui enjoys a delightful tropical climate, with temperatures ranging from a comfortable minimum of 24°C (76°F) to a maximum of 28°C (83°F). This month typically sees an average temperature of 27°C (80°F), making it an idyllic time for beachgoers and adventure seekers alike. As the months progress toward April and May, temperatures gradually rise, peaking at 31°C (88°F) in April. Interestingly, while January marks the start of the year with cooler evenings, the slight increases in February and March set the stage for the warmer months ahead. While February maintains the same maximum as January, temperatures consistently hover around the 27-28°C (81-83°F) range in the following months, offering a warm and inviting atmosphere for visitors. Overall, the January weather serves as a perfect prelude to the sun-kissed days that await in the bustling months of spring.

January Weather in Ko Samui: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Ko Samui, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Ko Samui, January typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec808182838383838282818180
Data source: Temperature data for Ko Samui generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Ko Samui

In January, Ko Samui welcomes the New Year with a moderate precipitation tally of 144 mm (5.7 inches) spread over 13 days. This sets the tone for the following months, as the rainfall significantly diminishes in February and March with only 39 mm (1.5 inches) and 38 mm (1.5 inches) respectively, offering a brief respite before the onset of the wet season. As the year progresses, April and May see a resurgence in rainfall, each with 144 mm and 126 mm, while the monsoon peaks dramatically in October and November, revealing water levels of 241 mm (9.5 inches) and 336 mm (13.2 inches) respectively. This pattern underlines a distinct seasonal rhythm, where January’s modest showers give way to drier days, only for the skies to open significantly later in the year, creating a lush, vibrant environment that characterizes Ko Samui.

January Precipitation Trends in Ko Samui

The chart displays monthly precipitation patterns in Ko Samui, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Ko Samui, January typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec1443938144126967980151241336207
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

January Humidity in Ko Samui

In January, Ko Samui greets visitors with a comfortable humidity level of 72%, setting a pleasant tone for the start of the year. As the months progress into February and March, the humidity dips slightly to 68%, offering a refreshing respite before it begins to rise again in April to 69%. However, the real change comes in May, where humidity jumps to 77%, and continues to climb through the summer months. June and July see elevated levels at 86%, while August peaks at a humid 88%. As the year winds down, humidity remains high—hovering around 86-87% from September to November—before finally decreasing to 83% in December. This trend indicates that while January is relatively comfortable, the later months bring a tropical intensity that is characteristic of Ko Samui's lush climate.

January Average Humidity in Ko Samui

This chart illustrates the average monthly humidity levels in Ko Samui, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Ko Samui is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec72%68%68%69%77%86%86%88%87%86%87%84%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Ko Samui

In January, Ko Samui experiences an intense UV Index of 11, highlighting the region's extreme sun exposure with a minimal burn time of just 10 minutes. This trend of extreme UV levels continues through the following months, peaking at 15 in both March and April. Even as the year progresses, the UV Index remains prominently high, ranging between 11 and 15 from January to May, before stabilizing at 14 through the later months, indicating that travelers should maintain vigilance against sunburn throughout the year. For more insights on UV exposure in this tropical paradise, check out Ko Samui UV Index.

Maximum UV Index Levels in Ko Samui for January

The chart shows the monthly maximum UV Index (UVI) for Ko Samui in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Ko Samui typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec111415151413141414141111
Data source: Ko Samui January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

January Sunshine in Ko Samui

January in Ko Samui, Thailand, shines brightly with 252 hours of glorious sunshine, setting a vibrant tone for the year. As the months progress, the island basks in even more light, peaking in March with a spectacular 346 hours of radiant sun. This trend of increasing sunshine continues until a slight dip in April, where the hours still remain plentiful, reflecting the island’s tropical charm. From May onward, the sun consistently embraces the skies, offering around 300 hours, ensuring visitors can revel in the beauty of this paradise. As the year winds down, while the sunlight slightly decreases, the allure of Ko Samui's warm, sun-kissed days remains a golden highlight worth experiencing.

Monthly Sunshine Duration in Ko Samui: January Highlighted

The January sunshine duration represents the total number of hours Ko Samui experiences direct sunlight during the month of January, excluding cloudy or obstructed periods. This chart compares the sunshine duration of January with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec252h308h346h318h331h308h314h300h286h287h289h302h
Data source: Ko Samui January Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Ko Samui During January

In Ko Samui, Thailand, the likelihood of sunny weather in January hovers at a modest 32%, setting the stage for a mix of bright skies and occasional clouds. Interestingly, this marks the start of a gradual increase in sunshine that peaks in February, soaring to 58%. However, as the year progresses, the probability of sun begins to wane, dipping to 21% by May and plummeting to a mere 9% in August. This trend showcases a pronounced fluctuation, with January offering a decent chance for sun, but leading into a decidedly wetter and cloudier stretch toward the latter half of the year. While December sees a slight uptick back to 39%, January remains a pivotal month for travelers seeking both sun and tropical charm.

Percentage of Sunny Days in January in Ko Samui

The chart illustrates the percentage of sunny days in Ko Samui throughout the year, with January highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Ko Samui experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec32%58%52%32%21%22%18%9%11%11%8%39%
Data source: Ko Samui January chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Ko Samui in January

In Ko Samui, Thailand, January ushers in a delightful 11 hours of daylight, setting the stage for sun-soaked adventures and serene beach lounging. This duration remains consistent into February, ensuring that visitors can still enjoy ample sunshine. As the months roll on into March, the daylight hours begin to increase, reaching 12 hours by mid-spring and maintaining this generous offering through the warm summer months of April to August. This steady availability of daylight creates a vibrant atmosphere, perfect for exploring the island’s natural beauty. However, as September transitions into October, daylight begins to contract once again, returning to 11 hours, reminiscent of the earlier months. The gradual shifts in daylight throughout the year not only highlight seasonal changes but also enhance the allure of Ko Samui, making it an idyllic getaway no matter the time of year.

Average Daylight Hours in Ko Samui for January

The chart illustrates the variation in daylight duration in Ko Samui throughout the year, with January highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 37m11h 48m12h 3m12h 19m12h 32m12h 39m12h 36m12h 24m12h 9m11h 53m11h 40m11h 33m
Data source: Ko Samui daylight hours, calculated by summing the hours between sunrise and sunset for each day.

January Winds in Ko Samui

In January, Ko Samui greets visitors with an inviting average wind speed of 5.2 m/s (12 mph), setting the stage for a pleasant tropical escape. This gentle breeze is a prelude to the slightly calmer conditions that follow in February, where winds dip slightly to 5.0 m/s (11 mph). As spring approaches, the winds begin to mellow further, reaching their lowest point in April at 3.5 m/s (8 mph). However, the trend shifts again as the mid-year peak approaches, with stronger breezes in July and December, both registering at 5.4 m/s (12 mph). Overall, January's breezy allure serves as a harbinger of the tropical charm that defines Ko Samui's enchanting atmosphere throughout the year, making it an ideal month for outdoor adventures and sun-soaked relaxation.

Average January Wind Speed in Ko Samui

The chart displays monthly wind speed patterns in Ko Samui, with values for each month shown alongside January's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how January's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec5.2 m/s5.04.63.54.04.85.44.74.54.75.05.4
Data source: Ko Samui January wind data, generated using information from the Copernicus Climate Change Service.

How January Weather in Ko Samui Compares to Other Months

Weather in Ko Samui varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Ko Samui, focusing on differences in temperature, rainfall, humidity, and UV levels.

January and February feature similar temperature ranges, with January experiencing a minimum of 24°C (76°F) and February a touch warmer at a minimum of 25°C (77°F). Both months maintain an average temperature of around 27°C (81°F) and peak at 28°C (83°F). However, January is significantly wetter, with 144 mm (5.7 in) of precipitation spread over 13 days, compared to February's much drier 39 mm (1.5 in) over just 8 days. Additionally, humidity levels are slightly lower in February at 68%, compared to January's 72%. For more details about weather conditions, you can check Ko Samui weather in February.

In January, the weather is warm with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F), accompanied by considerable rainfall of 144 mm (5.7 in) over 13 days, resulting in a humidity level of 72%. In contrast, March sees slightly higher temperatures with a minimum of 25°C (78°F) and a maximum of 30°C (86°F). The month experiences significantly less precipitation, totaling only 38 mm (1.5 in) over 7 days, and a slight decrease in humidity to 68%. For more detailed information on March weather, visit Ko Samui weather in March.

In January, the weather typically experiences a slightly cooler temperature range, with average highs around 28°C (83°F) and a minimum of 24°C (76°F). The month sees substantial rainfall, with about 144 mm (5.7 in) of precipitation spread over 13 days, contributing to a humidity level of 72%. In contrast, April brings warmer conditions, featuring higher average temperatures with a minimum of 25°C (77°F) and maximums reaching 31°C (88°F). Although April also records about 144 mm (5.7 in) of rain, it experiences slightly more rainy days—15 in total—while humidity levels drop to a more comfortable 69%. For more detailed information, you can visit Ko Samui weather in April.

In January, the weather is slightly cooler with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F), accompanied by significant rainfall of 144 mm (5.7 in) on about 13 days. The humidity stands at 72%, creating a warm and tropical atmosphere. In contrast, May sees an increase in temperature with a minimum of 26°C (79°F) and a maximum of 32°C (89°F), while average rainfall decreases to 126 mm (5.0 in) though spread over more days, specifically 22. The humidity also rises to 77%, making the air feel a bit more oppressive compared to January. For more details, check out Ko Samui weather in May.

In January, the weather is warm with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F), accompanied by an average temperature of 27°C (80°F). The month also sees significant rainfall, with 144 mm (5.7 in) distributed over approximately 13 days and a humidity level of 72%. In contrast, June experiences slightly higher temperatures, with a minimum of 26°C (79°F) and a maximum of 32°C (89°F), bringing an average temperature of 28°C (84°F). However, June has less precipitation, totaling 96 mm (3.8 in) over 18 days, and a higher humidity of 86%. For more details on the weather during this month, you can check Ko Samui weather in June.

In January, the weather in Ko Samui is pleasantly warm, with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F). The month experiences significant rainfall, totaling 144 mm (5.7 in) over approximately 13 days, along with a humidity level of 72%. In contrast, July offers slightly warmer conditions, with average temperatures from 26°C (80°F) to a maximum of 31°C (88°F). While precipitation is lower at 79 mm (3.1 in) over 17 days, humidity rises to 86%, making the air feel more humid and tropical. For a detailed look at July weather, you can visit Ko Samui weather in July.

When comparing the weather in January and August, it's clear that both months feature warm temperatures, but with some notable differences. January sees a slightly cooler range, with average temperatures around 27°C (80°F) and a maximum of 28°C (83°F), while August experiences warmer conditions, with average temperatures rising to 28°C (83°F) and maximum temperatures reaching 31°C (89°F). Precipitation is also varied, with January receiving 144 mm (5.7 in) over 13 days, compared to August's 80 mm (3.1 in) across 18 days. Additionally, humidity levels are higher in August, averaging 88% compared to January's 72%. For more details on the weather in August, you can check out Ko Samui weather in August.

In January, the weather is typically warm with average temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F). The month experiences around 144 mm (5.7 in) of rainfall over 13 days and boasts a humidity level of 72%. By contrast, September sees slightly higher temperatures, with a minimum of 26°C (78°F) and a maximum of 30°C (86°F), and an increase in precipitation to 151 mm (5.9 in) spread over 21 days. The humidity in September is also higher at 87%, creating a more humid atmosphere compared to January. For more detailed information on the weather during this month, check out Ko Samui weather in September.

In January, the weather is relatively warm with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F), averaging around 27°C (80°F). The month experiences moderate precipitation, totaling 144 mm (5.7 in) over approximately 13 days, with a humidity level of 72%. In contrast, October sees slightly higher temperatures, with a minimum of 25°C (77°F) and a maximum of 30°C (85°F), while maintaining the same average of 27°C (81°F). However, October is significantly wetter, receiving 241 mm (9.5 in) of rain over 28 days, contributing to higher humidity levels at 86%. For more detailed insights, you can check out Ko Samui weather in October.

In January, the weather is relatively warm with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 28°C (83°F) and an average of 27°C (80°F). The month experiences about 144 mm (5.7 in) of precipitation over 13 days, accompanied by a humidity level of 72%. In contrast, November offers slightly warmer conditions, with a minimum temperature of 25°C (77°F) and a maximum of 29°C (85°F), averaging also at 27°C (81°F). However, it is much wetter, receiving 336 mm (13.2 in) of rainfall over 24 days and higher humidity at 87%. For more details on the weather during this month, check Ko Samui weather in November.

Both January and December in Ko Samui exhibit a warm tropical climate, with average temperatures consistently hovering around 27°C (80°F). However, December tends to be slightly warmer with a maximum temperature of 29°C (84°F) compared to January's peak of 28°C (83°F). In terms of rainfall, December has significantly higher precipitation, totaling 207 mm (8.1 in) over 17 days, while January sees 144 mm (5.7 in) over just 13 days. Additionally, December's humidity levels are elevated at 83%, compared to January's 72%. For more details on the weather patterns, check out Ko Samui weather in December.

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Conclusion: What to Expect From January Weather in Ko Samui

As the first month of the year, January showcases warm and inviting weather in Ko Samui, making it an ideal time for travelers seeking sun and relaxation. With comfortable daily temperatures hovering around 27°C (80°F), visitors can enjoy outdoor activities without the intense heat typical of later months. While the island experiences some rainfall, with about 13 wet days throughout January, these brief showers are often followed by the sun re-emerging, contributing to the lush greenery that characterizes the landscape. The humidity remains moderate at 72%, adding to the tropical feel but not overwhelming. Overall, January stands out as a pleasant transition into the peak tourist season, offering a balance of warmth and occasional refreshment that differs from the more intense heat and humidity seen in the months to come. For a detailed overview of the weather patterns, visit Ko Samui Climate.