Thailand
Koh Samui in December: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Koh Samui in December is climatically well suited to beach holidays and family holidays. The average daily high is around 28 °C, and the sea is about 28 °C. With about 18 rainy days it is very wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
64/100 · #4
Warmth
#11
Dryness
#5
Sun
#11
Sea warmth
#11
Published best categories: Overall, Beach, Family
Koh Samui · DecemberPhoto: Sonia Selivonchik · CC BY-SA 4.0Climate facts
- Average high
- 28 °C
- Average low
- 26 °C
- Sea
- 28 °C
- Rainy days (est.)
- 18 rainy days (est.)
- Sun (est.)
- 5 h/day
- Humidity
- 80 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| November | 28 | 27 | 25 | 396 | 5.2 | 81 | 4.3 | 29 | 57 |
| December (selected) | 28 | 26 | 18 | 253 | 5.3 | 80 | 4.7 | 28 | 64 |
| January | 27 | 26 | 13 | 111 | 6.0 | 79 | 4.1 | 28 | 73 |
How do the previous and next months compare?
Baseline: December (64/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| November | -7 | +0.4 °C | +0.6 °C | +6.6 | +142.7 mm | -0.1 h | +1.8 % | -0.4 m/s | +0.6 °C |
| January | +9 | -0.3 °C | -0.4 °C | -5.7 | -141.9 mm | +0.7 h | -0.3 % | -0.5 m/s | -0.2 °C |
All twelve months in context
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Useful next decisions
Frequently asked questions
How warm is Koh Samui in December?
The average daily high is around 28 °C, with an average daily low of about 26 °C.
Can you swim in Koh Samui in December?
The sea is about 28 °C (very warm).
Does it rain a lot in Koh Samui in December?
The curated estimate is about 18 rainy days per month, not a directly measured long-term average. Total precipitation averages around 253 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Koh Samui?
By the climate score, January, February, March and December are the strongest months for Koh Samui. For a beach trip: January, February, March and December. December is one of them.