Ko Samui
9.51° N, 100.00° E
When to go?
Mean 26 °C, 10 rain days in the month (88 mm).
Good for
- Ideal for the seawater at 28 °C
Against
- Hothighs of 29 °C
Mean 27 °C, 6 rain days in the month (43 mm).
Good for
- Ideal for the seawater at 28 °C
Against
- Hothighs of 30 °C
Mean 28 °C, 7 rain days in the month (71 mm).
Good for
- Ideal for the seawater at 29 °C
Against
- Hothighs of 31 °C
Mean 29 °C, 11 rain days in the month (95 mm).
Good for
- Ideal for the seawater at 30 °C
Against
- Hothighs of 32 °C
Mean 29 °C, 19 rain days in the month (148 mm).
Against
- Hothighs of 32 °C
- Often rainyrain on 6 days in 10
Mean 29 °C, 18 rain days in the month (133 mm).
Against
- Hothighs of 32 °C
- Often rainyrain on 6 days in 10
Mean 28 °C, 18 rain days in the month (133 mm).
Against
- Hothighs of 31 °C
- Often rainyrain on 6 days in 10
Mean 28 °C, 18 rain days in the month (127 mm).
Against
- Hothighs of 31 °C
- Often rainyrain on 6 days in 10
Mean 28 °C, 21 rain days in the month (163 mm).
Against
- Hothighs of 31 °C
- Often rainyrain on 7 days in 10
Mean 27 °C, 25 rain days in the month (290 mm).
Against
- Hothighs of 30 °C
- Often rainyrain on 8 days in 10
Mean 27 °C, 23 rain days in the month (357 mm).
Against
- Hothighs of 29 °C
- Often rainyrain on 8 days in 10
- Torrential rain16 mm per rain day
Mean 27 °C, 15 rain days in the month (215 mm).
Good for
- Ideal for the seawater at 28 °C
Against
- Hothighs of 29 °C
- Often rainyrain on 5 days in 10
No ideal month: the best month is February, the least hot. Ideal for the sea: December–April. Avoid November–December (hot and often rainy, at times torrential rain), March–October (hot, at times often rainy), January (hot).
What is the climate like?
Temperature and rain
Monthly min and max temperature (°C)
Monthly min and max temperature (°C)
How much it rains
Rain days and how much water
Rain days and how much water
Bars: length = rain days, thickness = mm on a rain day, area = the month's rain. 3 mm a day7 mm a day15 mm a day
Colour = the month's rain: 103060100160250400mm
Daylight hours
Daylight and sky: sunrise, sunset and cloud cover
daylight under a clear sky (average share)daylight under cloud
daylight under a clear sky (average share)daylight under cloud
Times on the 15th of each month, in local time: daylight saving where and when it applies, standard time in the other months.
Sea temperature: Gulf of Thailand
Monthly mean sea temperature: Gulf of Thailand (°C)
Monthly mean sea temperature: Gulf of Thailand (°C)
Effect of climate change
Today's climate (1996–2025) compared with 1961–1990:
In short
Year by year
Temperature of each year
Against 1961–1990 the mean temperature of today (1996–2025) has changed by +0.4 °C; in the last ten years by +0.7 °C. Warmest year: 2024 (+1.3 °C), coldest: 1956 (−0.5 °C).
January and November warmed the most (+0.6 and +0.6 °C), October the least (+0.3 °C).
Warming stripes: after an idea by Ed Hawkins (University of Reading), showyourstripes.info, CC BY 4.0.
Rain of each year (% against 1961–1990)
more rain than in 1961–1990less rain
Rain in a year: no clear trend, dry and wet years alternate as before.
The sea, then and now
+0.4 °Cthe sea today, compared with 1961–1990