Koh Samui weather in December
Monthly temperatures, rain, humidity, what to wear and what to pack — 2024–2025 historical average
Koh Samui December weather at a glance
In December, Koh Samui averages 23.3°C, with typical highs of 25.4°C and lows of 21.6°C. The historical average is 16 wet days and 81% humidity.
Koh Samui December temperature & humidity
Koh Samui December rain & wet days
Pack a light rain jacket, waterproof pouch and quick-dry shoes. Keep an indoor stop available between outdoor activities.
What to wear in Koh Samui in December
Choose breathable summer clothes and pack sun protection. Rain is frequent at roughly 16 days in the month; pack a rain jacket and water-resistant shoes. High humidity makes quick-dry clothing and a spare top especially useful.
- DaytimeBreathable short sleeves, hat and sunscreen · average high 25.4°C
- Morning & eveningLight layer for air-conditioned rooms · average low 21.6°C
- FootwearComfortable walking shoes; quick-dry footwear for rainy days.
Packing essentials
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Koh Samui December sunrise & sunset times
2026 December · Local time (Asia/Bangkok)
| Date | Sunrise | Sunset | Daylight |
|---|---|---|---|
| 2026-12-01 | 06:20 | 17:57 | 11h 37m |
| 2026-12-15 | 06:28 | 18:02 | 11h 35m |
| 2026-12-31 | 06:35 | 18:10 | 11h 35m |
For sunset photos, arrive before the listed sunset time. Clouds, mountains and buildings can change when the sun becomes visible or disappears.
Calculated for the city coordinates with daylight saving applied. SunCalc · tz-lookup
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Koh Samui rainy season & dry season
Is December wet or dry?
Thailand’s southwest monsoon generally brings rain from mid-May to mid-October. The southern east coast also receives northeast-monsoon rain, so Koh Samui and Phuket do not share one wet/dry-season calendar. The 2024–2025 average for December is 16 wet days.
2024–2025 wet-day averages, not long-term season boundaries. Wet days do not mean all-day rain.
Packing for rainy and dry periods
For rainy periods, bring a light rain jacket, a waterproof pouch and quick-dry clothes. In drier months, pack sunscreen and a hat, plus a compact umbrella for showers. For beach trips, check the boat operator’s weather and cancellation notices.
Season guide: Thailand Government
Koh Samui travel essentials
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Best months to visit Koh Samui
Bar height shows our simple weather-comfort score, not a safety rating; colour shows temperature.
December weather by year
Daily weather in 2025
Daily high and low temperatures; blue labels show precipitation
Frequently asked questions
What is Koh Samui weather like in December?
In December, Koh Samui averages 23.3°C, with typical highs of 25.4°C and lows of 21.6°C. The historical average is 16 wet days and 81% humidity. Our weather-comfort rating for this month is fair.
Does it rain a lot in Koh Samui in December?
There are about 16 wet days in December. Pack a rain jacket and water-resistant shoes.
What should I wear in Koh Samui in December?
Choose breathable summer clothes and pack sun protection. Rain is frequent at roughly 16 days in the month; pack a rain jacket and water-resistant shoes. High humidity makes quick-dry clothing and a spare top especially useful.
What are the best months to visit Koh Samui?
Recent weather data rates March among the more comfortable months.
Where can I check Koh Samui weather in December in real time?
Check local webcams for the view right now and a local weather service for today’s forecast. Monthly temperatures here are historical averages.
Is December rainy or dry season in Koh Samui?
Thailand’s southwest monsoon generally brings rain from mid-May to mid-October. The southern east coast also receives northeast-monsoon rain, so Koh Samui and Phuket do not share one wet/dry-season calendar. The 2024–2025 average for December is 16 wet days.
Which months have fewer rainy days in Koh Samui?
In our 2024–2025 data, March, April, February have the fewest wet days. These are recent observations, not long-term climate normals. Compare temperatures and your planned activities as well.
What time are sunrise and sunset in Koh Samui in December?
On 2026-12-15, calculated sunrise is 06:28 and sunset is 18:02 in local time (Asia/Bangkok). Times vary by date and terrain.
Koh Samui weather by month
More Southeast Asia destinations in December
Open-Meteo (CC BY 4.0) · 2024–2025 historical data, aggregated and rounded by this site. Not a forecast or long-term climate normal. Calculation method and limitations