Ko Samui weather in December
December in Ko Samui: hot, rainy, with very humid — a great time to visit.
#9 of 12 months in Ko Samui · #230 of 604 destinations to visit in December · comfort 75/100 (tier B)
Updated June 2026 · climate normals from ERA5 reanalysis
Ko Samui climate normals — December
| Daytime high | 28°C / 82°F | 🥵 hot |
|---|---|---|
| Nighttime low | 26°C / 79°F | |
| Feels like (high) | 31°C / 88°F | |
| Rainfall | 141 mm / 5.6 in | 🌧 rainy |
| Rainy days | 14 days | |
| Humidity | 78% | 💦 very humid |
| Dew point | 23°C / 73°F | |
| Sunshine | 9.7 h/day | |
| Daylight | 11.6 h | |
| Wind | 24 km/h / 15 mph | |
| Air quality (US AQI) | 52 | 🙂 moderate |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Ko Samui?
Loading map…
Ko Samui in December — FAQ
- Is December a good time to visit Ko Samui?
- December in Ko Samui: hot, rainy, with very humid — a great time to visit. It ranks #9 of 12 months for Ko Samui on SeasonMap's comfort score (75/100).
- What is the weather like in Ko Samui in December?
- In December, Ko Samui averages a daily high of 27.7°C and a low of 26°C, with about 141.2 mm of rain over roughly 14 rainy days.
- What is the air quality in Ko Samui in December?
- Ko Samui has a mean US Air Quality Index of about 52 in December.