For beach walks and a leisurely resort holiday on Koh Samui, choose February–April. Unlike Phuket and Krabi, Samui is wet in October–December: November averages 444.6mm, so the same dry-season calendar will not work for both coasts. February is the driest month at 64.3mm, with a mean temperature of 27.4°C. It becomes hotter towards April. Plan beach walks for the morning and evening and rest at your accommodation during the middle of the day.
The figures below are 1991–2020 climate normals from station KO SAMUI. Actual weather at beaches, mountains and accommodation may differ. Scroll the table horizontally.
| Month | Mean temperature | Average high | Average low | Rainfall | Rainy days |
|---|---|---|---|---|---|
| January | 26.9°C | 29.0°C | 24.2°C | 126.8mm | 11.1 days |
| February | 27.4°C | 29.4°C | 24.9°C | 64.3mm | 5.6 days |
| March | 28.2°C | 30.4°C | 25.4°C | 115.8mm | 5.9 days |
| April | 29.1°C | 31.8°C | 26.0°C | 82.9mm | 8.1 days |
| May | 29.2°C | 32.9°C | 25.7°C | 131.6mm | 14.0 days |
| June | 28.8°C | 32.7°C | 25.3°C | 133.6mm | 13.1 days |
| July | 28.5°C | 32.3°C | 25.1°C | 117.0mm | 14.3 days |
| August | 28.4°C | 32.4°C | 25.1°C | 102.2mm | 14.5 days |
| September | 28.0°C | 31.9°C | 24.8°C | 117.5mm | 15.0 days |
| October | 27.4°C | 30.6°C | 24.3°C | 294.9mm | 19.3 days |
| November | 27.1°C | 29.7°C | 24.1°C | 444.6mm | 18.7 days |
| December | 26.8°C | 29.3°C | 24.0°C | 263.1mm | 14.2 days |
The station table used is on PDF page 77. Rainy days are averages and do not mean rain throughout the day.
Opportunities and cautions are itinerary suggestions based on climate data. Check your day’s weather and whether marine activities are operating separately before departure.
What suits this month
Plan both time resting at your accommodation and visits to a nearby beach. Stay indoors while it rains and go out again once it eases.
Things to consider
During a seasonal transition, do not expect uninterrupted sunshine. Check the forecast before making outdoor bookings.
What suits this month
Walk beside the sea in the morning and rest at your accommodation during the day. This suits a trip combining beach walks and relaxation.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Save seaside walks for the morning or late afternoon, with meals and rests at your accommodation during the day.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Walk on the beach in the morning or evening and rest at your accommodation during the hot part of the day. Breaks between meals and outings avoid long periods outside at midday.
Things to consider
Long walks in the midday heat can be tiring. Carry water and stop in the shade between journeys.
What suits this month
Enjoy beach walks at the cooler times of day. Eat indoors or rest at your accommodation during the day and go out again as the sun drops.
Things to consider
Long walks in the midday heat can be tiring. Carry water and stop in the shade between journeys.
What suits this month
Visit the beach in the morning and rest at your accommodation during the day. You can enjoy the sea views while avoiding the midday heat.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Plan beach walks alongside time to relax at your accommodation. Eat indoors during the hot hours and go out again as the sun drops.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Enjoy a relaxing holiday with time at your accommodation and sea views. If you want to walk, go in the morning or evening rather than the midday heat.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Walk on the beach in the morning, then rest at your accommodation. Returning to the seafront in the evening lets you avoid the midday heat.
Things to consider
Even with little rain, midday can be hot and showers are possible. Bring a hat and a light umbrella.
What suits this month
Rest at your accommodation or eat indoors during heavy rain. Take short walks nearby when it eases.
Things to consider
Check waves and wind as well as rain. Change your plans if boats are not sailing or swimming is prohibited at the beach.
What suits this month
Leave plenty of time to relax at your accommodation and enjoy meals nearby. Arrange outdoor visits around the day’s rain forecast.
Things to consider
Check waves and wind as well as rain. Change your plans if boats are not sailing or swimming is prohibited at the beach.
What suits this month
Enjoy leisurely meals indoors and time relaxing at your accommodation. Take a short walk nearby when the rain eases.
Things to consider
Check waves and wind as well as rain. Change your plans if boats are not sailing or swimming is prohibited at the beach.
Plan Beach walks for the morning or around sunset. Meals and rests at midday avoid long walks in the hottest hours. On rainy days, try resting at your accommodation between meals and short outings.
Before entering the sea, follow beach flags and swimming prohibitions. For island tours and boat journeys, follow the operator’s guidance that day and read cancellation and amendment conditions before booking.
February–April suits a beach holiday. Samui is wet towards the end of the year, so do not simply use Phuket’s recommended months. February has the lowest rainfall, while April’s mean temperature rises to 29.1°C. Consider how comfortably you cope with heat as well as rainfall when choosing your dates.
Look at average highs and lows too. Mean temperature is not the temperature at a particular time of day. Prepare separately for midday walks and morning or evening outings.
No. Rainy days are a monthly average, not a measure of when rain falls or how long it lasts. Use the hourly forecast for your actual travel dates to adjust outdoor plans.
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