Thailand
Koh Samui in January: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Koh Samui in January is climatically well suited to beach holidays, family holidays and city breaks. The average daily high is around 27 °C, and the sea is about 28 °C. With about 13 rainy days it is wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
73/100 · #3
Warmth
#12
Dryness
#3
Sun
#9
Sea warmth
#12
Published best categories: Overall, Beach, City break, Family
Koh Samui · JanuaryPhoto: Sonia Selivonchik · CC BY-SA 4.0Climate facts
- Average high
- 27 °C
- Average low
- 26 °C
- Sea
- 28 °C
- Rainy days (est.)
- 13 rainy days (est.)
- Sun (est.)
- 6 h/day
- Humidity
- 79 %
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 |
|---|---|---|---|---|---|---|---|---|---|
| December | 28 | 26 | 18 | 253 | 5.3 | 80 | 4.7 | 28 | 64 |
| January (selected) | 27 | 26 | 13 | 111 | 6.0 | 79 | 4.1 | 28 | 73 |
| February | 28 | 26 | 7 | 59 | 7.0 | 79 | 3.7 | 28 | 83 |
How do the previous and next months compare?
Baseline: January (73/100)
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 | |
|---|---|---|---|---|---|---|---|---|---|
| December | -9 | +0.3 °C | +0.4 °C | +5.7 | +141.9 mm | -0.7 h | +0.3 % | +0.5 m/s | +0.2 °C |
| February | +10 | +0.4 °C | +0.3 °C | -6 | -51.7 mm | +1 h | -0.5 % | -0.4 m/s | +0.4 °C |
All twelve months in context
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Where to stay in Koh Samui
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Useful next decisions
Frequently asked questions
How warm is Koh Samui in January?
The average daily high is around 27 °C, with an average daily low of about 26 °C.
Can you swim in Koh Samui in January?
The sea is about 28 °C (very warm).
Does it rain a lot in Koh Samui in January?
The curated estimate is about 13 rainy days per month, not a directly measured long-term average. Total precipitation averages around 111 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. January is one of them.