For a Koh Samui holiday with beach walks and unhurried time at your accommodation, choose February–April. Unlike Phuket and Krabi, Samui has heavy rain in October–December, reaching 444.6mm in November, so the same dry-season calendar does not apply. February is the driest month at 64.3mm and averages 27.4°C. It becomes hotter towards April: rest indoors around midday and enjoy beach walks in the morning and evening.
The figures below are 1991–2020 climate normals. The station is KO SAMUI; conditions at beaches, mountains and your accommodation can differ. Scroll the table horizontally.
| Month | Average temperature | Average high | Average low | Rainfall | Rainy days |
|---|---|---|---|---|---|
| Month 1 | 26.9°C | 29.0°C | 24.2°C | 126.8mm | 11.1 days |
| Month 2 | 27.4°C | 29.4°C | 24.9°C | 64.3mm | 5.6 days |
| Month 3 | 28.2°C | 30.4°C | 25.4°C | 115.8mm | 5.9 days |
| Month 4 | 29.1°C | 31.8°C | 26.0°C | 82.9mm | 8.1 days |
| Month 5 | 29.2°C | 32.9°C | 25.7°C | 131.6mm | 14.0 days |
| Month 6 | 28.8°C | 32.7°C | 25.3°C | 133.6mm | 13.1 days |
| Month 7 | 28.5°C | 32.3°C | 25.1°C | 117.0mm | 14.3 days |
| Month 8 | 28.4°C | 32.4°C | 25.1°C | 102.2mm | 14.5 days |
| Month 9 | 28.0°C | 31.9°C | 24.8°C | 117.5mm | 15.0 days |
| Month 10 | 27.4°C | 30.6°C | 24.3°C | 294.9mm | 19.3 days |
| Month 11 | 27.1°C | 29.7°C | 24.1°C | 444.6mm | 18.7 days |
| Month 12 | 26.8°C | 29.3°C | 24.0°C | 263.1mm | 14.2 days |
The station table is on PDF page 77. Rainy-day counts are averages and do not mean rain lasts all day.
The suggestions and cautions are editorial itinerary advice based on climate figures. Check the day’s weather and marine activity operations separately before setting out.
What to enjoy this month
Plan time to rest at your accommodation as well as outings to the nearby beach. Stay indoors during rain and go out again once it eases.
What to bear in mind
Clear weather is less certain during the seasonal transition. Look at the forecast before making outdoor bookings.
What to enjoy this month
Walk beside the sea in the morning and rest at your accommodation during the day. This suits a holiday combining beach walks and relaxation.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Walk beside the sea in the morning or late afternoon, with a meal or rest at your accommodation during the day.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Take beach walks in the morning or evening and rest at your accommodation during the hot afternoon. Breaks between meals and outings reduce time outdoors at midday.
What to bear in mind
Long walks around midday can be tiring in the heat. Carry water and take breaks in the shade between outings.
What to enjoy this month
Walk along the beach in the less hot hours. Eat indoors or rest at your accommodation during the day, then go out again as the sun gets lower.
What to bear in mind
Long walks around midday can be tiring in the heat. Carry water and take breaks in the shade between outings.
What to enjoy this month
Explore the beach in the morning and rest at your accommodation during the day. You can enjoy sea views while avoiding the midday heat.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Alternate beach walks with time to rest at your accommodation. Eat indoors during hot hours and go out again as the sun gets lower.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Enjoy a holiday relaxing at your accommodation and looking out to sea. If you want to walk, go out in the morning or evening rather than the hot afternoon.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Walk along the beach in the morning, then rest at your accommodation. Return to the shore in the evening to avoid the midday heat.
What to bear in mind
Even with less rain, midday is hot and showers are possible. Pack a hat and a light umbrella.
What to enjoy this month
Rest at your accommodation or eat indoors during heavy rain. When it eases, take a short walk nearby.
What to bear in mind
Check wind and waves as well as rain. Adjust plans to boat operating decisions and swimming prohibitions at the beach.
What to enjoy this month
Leave plenty of time to rest at your accommodation and enjoy meals nearby. Arrange outdoor sightseeing around the day’s rain forecast.
What to bear in mind
Check wind and waves as well as rain. Adjust plans to boat operating decisions and swimming prohibitions at the beach.
What to enjoy this month
Take your time over meals indoors and rest at your accommodation. When rain eases, go for a short walk nearby.
What to bear in mind
Check wind and waves as well as rain. Adjust plans to boat operating decisions and swimming prohibitions at the beach.
Plan Beach walks for the morning or around sunset. Leave time for meals and rest at midday so that you are not walking for long during the hottest hours. On rainy days, switch to time at your accommodation with meals and short outings.
Before entering the sea, follow beach flags and swimming prohibitions. Follow the operator’s instructions for island tours and boat journeys, and read cancellation and change conditions before booking.
February–April suits a beach holiday. Koh Samui has heavy rain towards the end of the year, so Phuket’s recommended months cannot simply be copied. February has the least rain, while April’s average temperature rises to 29.1°C. Consider how comfortable you are in the heat when choosing dates.
Look at average highs and lows too. The mean is not the temperature at a particular hour. Prepare separately for midday walks and outings in the morning or at night.
No. Rainy-day counts are monthly averages and do not say when or how long it rains. Use the hourly forecast for your actual dates to adjust outdoor plans.
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