Ko Samui weather by month & the best time to visit
🇹🇭 Thailand · beach resort · tropical monsoon climate
The best time to visit Ko Samui is February — its sunniest month (Sunshine Score 86/100), with April close behind. Ko Samui averages about 2,342 hours of sunshine a year. Daytime highs around 28°C / 82°F and roughly 38 mm of rain in February.
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- Sun hours / year
- 2,342
- Sunniest month
- February
- Peak score
- 86/100
- Rain / year
- 2,088 mm
- Midday UV at peak
- 11 (extreme)
- Sea at warmest
- 33°C / 91°F
- Population
- 50k
- Elevation
- Sea level
When is the best time to visit Ko Samui?
For sunshine, the best time to visit Ko Samui is February, then April. The dullest month is May (65/100, 170 mm of rain). The full month-by-month picture is in the table below.
How sunny is Ko Samui?
Ko Samui gets a moderate 2,342 hours of sunshine a year. February (86/100) is noticeably better than May (65). It ranks #12 of 24 destinations in Thailand for annual sunshine, above the national median of 2,329 hours. Rain has a clear season: the wettest stretch, around November, carries about 42% of the annual 2,088 mm.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV | Sea |
|---|---|---|---|---|---|---|
| January | 68 | 28° / 82°F | 26° / 79°F | 135 mm | 9 | 29° / 84°F |
| February | 86 | 28° / 82°F | 26° / 79°F | 38 mm | 11 | 30° / 86°F |
| March | 72 | 29° / 84°F | 27° / 81°F | 114 mm | 11 | 30° / 86°F |
| April | 76 | 30° / 86°F | 28° / 82°F | 90 mm | 11 | 32° / 90°F |
| May | 65 | 30° / 86°F | 29° / 84°F | 170 mm | 10 | 33° / 91°F |
| June | 65 | 30° / 86°F | 28° / 82°F | 167 mm | 10 | 31° / 88°F |
| July | 65 | 29° / 84°F | 28° / 82°F | 166 mm | 10 | 31° / 88°F |
| August | 66 | 29° / 84°F | 27° / 81°F | 144 mm | 10 | 31° / 88°F |
| September | 65 | 29° / 84°F | 27° / 81°F | 181 mm | 10 | 30° / 86°F |
| October | 65 | 28° / 82°F | 27° / 81°F | 246 mm | 9 | 31° / 88°F |
| November | 65 | 28° / 82°F | 27° / 81°F | 375 mm | 8 | 30° / 86°F |
| December | 65 | 28° / 82°F | 27° / 81°F | 262 mm | 8 | 29° / 84°F |
Sea temperature in Ko Samui by month
The sea off Ko Samui is warmest in May at around 33°C / 91°F, and coolest in January at 29°C / 84°F. The water sits at a comfortable 21°C or warmer roughly all year round. Month-by-month sea-surface temperatures are in the Sea column of the table above.
See Ko Samui on the interactive sunshine globe →
Nearby places for sunshine
- Surat Thani Thailand · 112 km · best in Feb · 2,175 h sun/yr
- Nakhon Si Thammarat Thailand · 113 km · best in Feb · 2,056 h sun/yr
- Krabi Thailand · 200 km · best in Feb · 2,260 h sun/yr
- Trang Thailand · 232 km · best in Feb · 2,251 h sun/yr
- Phuket Thailand · 249 km · best in Feb · 2,260 h sun/yr
- Hat Yai Thailand · 293 km · best in Feb · 2,253 h sun/yr
Nearest destinations
- Chumphon Thailand · 150 km · 2,206 h sun/yr · best in Feb
- Ranong Thailand · 164 km · 2,111 h sun/yr · best in Feb
- Kawthoung Myanmar (Burma) · 176 km · 2,055 h sun/yr · best in Feb
Head-to-head
How Ko Samui compares month by month: Ko Samui vs Nakhon Si Thammarat · Ko Samui vs Surat Thani · Ko Samui vs Rayong · Ko Samui vs Krabi · all comparisons
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