Best Time to Visit Koh Samui
Koh Samui is best visited All year, when skies are clearer and temperatures are warm without being extreme.
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Once you know the best time to go, find out exactly what to pack for Koh Samui at 247PackingList — climate-matched checklists for every destination. For country facts like currency, language and plug type, see our Thailand country guide at 247CountryInfo. Some travellers fund a longer stay in Koh Samui by teaching English along the way — a TEFL certificate is usually all it takes.
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Compare car hire prices → Affiliate link — we earn a commission at no extra cost to youKoh Samui — Monthly Temperatures
Average daily high and low temperatures (°C/°F). Bars show the daily range each month.
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| Month | High | Low | Rain | Sun/day | Rainy days | Rating |
|---|---|---|---|---|---|---|
| January Best | 28.5°C | 24.3°C | 43.1mm | 10.4h | 14 | 10/10 |
| February Best | 29.0°C | 24.5°C | 58.2mm | 10.5h | 14 | 10/10 |
| March Best | 30.5°C | 25.4°C | 36.5mm | 10.9h | 9 | 10/10 |
| April Best | 31.1°C | 26.3°C | 106.9mm | 10.7h | 16 | 9/10 |
| May Best | 31.0°C | 26.5°C | 134.5mm | 10.4h | 20 | 9/10 |
| June Best | 30.6°C | 26.2°C | 102.4mm | 10.3h | 18 | 9/10 |
| July Best | 30.0°C | 25.9°C | 149.9mm | 8.8h | 22 | 9/10 |
| August Best | 30.4°C | 26.0°C | 114.2mm | 9.4h | 21 | 9/10 |
| September Best | 29.2°C | 25.4°C | 196.8mm | 8.5h | 22 | 9/10 |
| October Best | 28.5°C | 24.8°C | 244.4mm | 8.5h | 28 | 8/10 |
| November Best | 28.1°C | 24.5°C | 323.1mm | 8.0h | 26 | 8/10 |
| December Best | 27.9°C | 24.4°C | 161.7mm | 9.7h | 19 | 9/10 |
Koh Samui Climate
Koh Samui has a tropical climate — hot and humid year-round with a distinct wet season. Check the annual climate overview for Koh Samui for the full year picture, or read the dedicated Koh Samui rainy season guide.
Counting down to your trip? Use our holiday countdown timer at LeftToTime to track the days. Owners often keep a Koh Samui travel guide to hand for planning on the go. Check clothing sizes in Thailand at 247Sizing before you shop.
Frequently Asked Questions
What is the best month to visit Koh Samui?
The best month to visit Koh Samui is January, when temperatures average 28.5°C and conditions score 10/10 for comfort.
What is the weather like in Koh Samui in January?
January in Koh Samui is hot, with average highs of 28.5°C and lows of 24.3°C. It is moderately rainy (14 rainy days), with roughly 10.4 hours of sunshine a day. It is one of the best months of the year to visit.
When is rainy season in Koh Samui?
Rainy season in Koh Samui runs April, May, June, July, August, September, October, November, December. Expect heavy downpours and high humidity. Full rainy season guide →
Is Koh Samui good to visit in winter?
Yes — winter (December, January, February) averages 28.5°C highs with a 10/10 comfort rating, making it a solid time to visit.
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Climate data sourced from Open-Meteo (open source, open data licence). Monthly averages calculated from 2020–2023 historical data. Weather can be unpredictable — always check a live forecast before travelling.