Thailand Koh Samui Weather in January — Climate Guide
January in Koh Samui is high
Koh Samui Weather in January — Quick Answer
As of 2026- Avg temp
- 29° / 24°
- Rainfall
- 180mm · 14 days
- Crowds
- Very busy
As of 2026, Koh Samui in January averages a high of 29°C and low of 24°C with 180mm of rain over about 14 days. Tail end of the wet season into the dry. Around 29°C/24°C, warm and humid. Light, breathable clothing, swimwear, a hat, and SPF 50+; pack a light rain layer for the early-month showers that ease as the month goes on. Sea ~29°C.
January is high for Koh Samui.
January is the transition from Koh Samui's wet season into its best dry window. It averages 29°C/24°C with rainfall easing through the month (around 180mm, front-loaded early).
Early January can still see leftover northeast-monsoon showers, but from mid-to-late January the skies clear, the seas calm, and boat trips to Ang Thong, Koh Phangan, and Koh Tao become reliable again. Late January is genuinely excellent.
Travel score
Koh Samui January Weather Stats
Avg High
29°C
Avg Low
24°C
Rainy Days
14
180mm total
Sunshine
6.5h
Daily avg
Humidity
82%
muggy
UV Index
10
Very high
Wind
14 km/h
Gusts 26
Sea Temp
29°C
Avg water temp
Crowds
Very busy
At attractions
January Sunrise & Sunset
Air Quality
PM2.5
14 μg/m³
PM10
26 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
33°C
Nighttime
26°C
Humidity and wind affect how the actual temperature feels.
Wind
14 km/h
Max gust 26 km/h
Activities Recommended for January
January Travel Pros & Cons
Pros
- Weather improving fast — late January is excellent
- Calmer seas returning for boat trips
- Warm sea (~29°C) and hot, sunny days by mid-month
- Opposite season to rainy Phuket/Krabi
Cons
- Early-month leftover monsoon showers possible
- Yearly-peak prices over New Year
- Book Christmas/New Year 4-6 months ahead
January Events & Festivals
- New Year peak travel (early January)
- Wet season tapering off — drier from mid-to-late January
- Calmer seas returning for boat trips by late month
- Chinese New Year approaches (late Jan/early Feb in some years)
Koh Samui in January — Full Picture
January is the transition from Koh Samui's wet season into its best dry window. It averages 29°C/24°C with rainfall easing through the month (around 180mm, front-loaded early).
Early January can still see leftover northeast-monsoon showers, but from mid-to-late January the skies clear, the seas calm, and boat trips to Ang Thong, Koh Phangan, and Koh Tao become reliable again. Late January is genuinely excellent.
Note the Gulf timing: while Phuket and Krabi on the Andaman coast are in peak dry season, Samui is just emerging from its wettest stretch — the two coasts run opposite monsoons.
The New Year period (early January) is a yearly travel peak with the highest hotel prices; book Christmas/New Year 4-6 months ahead. Prices ease a little once the holidays pass, making late January good value with improving weather.
The sea stays a warm ~29°C year-round, so swimming is fine throughout — it's clarity and calm seas, not water temperature, that improve in the dry season.
What to Wear & What to Pack
Tail end of the wet season into the dry. Around 29°C/24°C, warm and humid. Light, breathable clothing, swimwear, a hat, and SPF 50+; pack a light rain layer for the early-month showers that ease as the month goes on. Sea ~29°C.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
31.7°C
25°C
10/mo
Summer (Jun·Jul·Aug)
32°C
25°C
13.3/mo
Autumn (Sep·Oct·Nov)
30°C
24.3°C
18/mo
Winter (Dec·Jan·Feb)
Current29°C
24°C
12.3/mo
Koh Samui Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 29° | 24° | 14d·180mm | 6.5h | 82% | 10 | Very busy | Peak | |
| February (Best) | 30° | 24° | 6d·60mm | 8h | 78% | 11 | Very busy | Peak |
| March (Best) | 31° | 25° | 7d·75mm | 8.5h | 78% | 12 | Busy | Peak |
| 32° | 25° | 9d·100mm | 8.5h | 78% | 12 | Busy | Peak | |
| 32° | 25° | 14d·150mm | 7h | 80% | 11 | Moderate | Shoulder | |
| 32° | 25° | 13d·110mm | 7.5h | 78% | 11 | Busy | Shoulder | |
| 32° | 25° | 13d·110mm | 7.5h | 78% | 11 | Very busy | Peak | |
| 32° | 25° | 14d·110mm | 7h | 78% | 11 | Very busy | Peak | |
| 31° | 25° | 15d·150mm | 6h | 80% | 10 | Moderate | Shoulder | |
| 30° | 24° | 19d·290mm | 5h | 84% | 9 | Quiet | Low season | |
| 29° | 24° | 20d·340mm | 4.5h | 85% | 9 | Quiet | Low season | |
| 28° | 24° | 17d·230mm | 5h | 84% | 9 | Very busy | Peak |
View Other Months
Koh Samui January Hotel Picks
Frequently Asked Questions
Is January a good time to visit Koh Samui?
Koh Samui in January is high. Tourist crowds are very busy and flight/hotel prices are peak.
What's the average temperature in Koh Samui in January?
Koh Samui January averages a high of 29°C and a low of 24°C.
Does it rain much in Koh Samui in January?
Koh Samui January averages 180mm of rainfall over about 14 rainy days.
What should I wear in Koh Samui in January?
Tail end of the wet season into the dry. Around 29°C/24°C, warm and humid. Light, breathable clothing, swimwear, a hat, and SPF 50+; pack a light rain layer for the early-month showers that ease as the month goes on. Sea ~29°C.
What time are sunrise and sunset in Koh Samui in January?
Koh Samui January sunrise is 06:25 and sunset is 18:15, with 11h 50min of daylight.
What's the air quality like in Koh Samui in January?
Koh Samui January air quality (AQI) averages 38, rated Good. PM2.5 averages 14μg/m³.
What activities are recommended in Koh Samui in January?
In January, Koh Samui is great for Ang Thong Marine Park boat trip (calmer late month), Big Buddha + island temple loop, Chaweng/Lamai beach days.
Is January peak season in Koh Samui?
Koh Samui January crowds are very busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit Koh Samui
View Other Months
Planning a January trip to Koh Samui?
You've checked the weather — next come the budget and the route.
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.