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Koh Samui, Thailand · Equatorial tropical

Koh Samui in March: go or not?

Mixed period. Koh Samui in March: 5.9/10.

📅 Data updated: October 2026 🛰️ ERA5 · 10 years 📍 9.51°N · 100.06°E
⚡ This month's verdict
Why not
Koh Samui · March
5.9
26–30°
Temperature
15%
Rain
8h
Sun
🌴 Tropical☀️ High UV🌧️ Monsoon season
Photo : RODOLFO BARRETTO via Unsplash
The month in detail

What to expect in March

March is peak dry season in Koh Samui. The air is warm and humidity more bearable than in the rainy season. Rain risk remains low (15% of days), leaving good room for outdoor activities. Not the best window, but acceptable if dates are constrained. February (6.0/10) is significantly better if possible.

March ranks 2 out of 12 months in Koh Samui.

This month's conditions

What it's like in March

UV index
9 · very high
protection essential
Feels like
very humid
23°
Sea
29°C
warm, ideal
Daylight
11.9h of daylight
Air quality
good
AQI 30
Compare

Is March the right month?

The best month in Koh Samui is February (6.0/10), 0.1 pt higher than March.

See February →See all 12 months →
Book

Plan your trip

Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.

🎟️ Activities & tours · Koh Samui

GetYourGuide selection · free cancellation

See all →
Affiliate link · GetYourGuide
Practical info

What you need to know before you go

Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a tropical stay.

Country · Thailand

🗣️LanguageThai
💶CurrencyThai Baht (฿)
🚗DrivingLeft-hand
🛡️Safety ⓘSafe · 2/5
💰Cost of living ⓘCheap · 2/5

🌡️ Climate

🌍Climate typeEquatorial tropical
📈Climate trend ⓘStable
🔥Hottest monthApril · 31°C
❄️Coolest monthJanuary · 28°C
🌧️Rainiest month ⓘNovember · 55%

🏝️ Tropical stay

🌞Dry season ⓘMay → Sep
🌧️Wet season ⓘDec → Mar
🌀Cyclones ⓘNone (equator)
Location

Where is Koh Samui ?

Global position + regional geographic context.

🌍 World
🔍 Geographic context
Thailand
Equatorial tropical climate with a 6.0 → 4.9 gap between best and worst month. 10 years of ERA5 data to choose by project.
9.51°N · 100.06°E
Questions

Frequently asked questions

What is the best time to visit Koh Samui?
February is the best month with 29.0°C highs, 25.0°C lows, 7.6h of sunshine and 15.0% rainy days.
How many hours of sunshine does Koh Samui get in February?
Koh Samui averages 7.6 sunshine hours per day in February. It is the sunniest month with a climate score of 5.9/10.
What is the rainiest month in Koh Samui?
October is the most unfavourable month with October has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Koh Samui in February?
In February, overnight lows reach 25.0°C, while afternoon highs average 29.0°C.
Is Koh Samui good in winter?
In winter (December-February), Koh Samui scores 5.5/10 on average — Decent period conditions for cultural visits.. The best month overall remains February with a score of 5.9/10.
When should you avoid Koh Samui?
October is the most difficult month to visit Koh Samui, with October has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.
Can you swim in Koh Samui in March?
In March, the sea averages 29°C in Koh Samui: warm, ideal. Ideal conditions for swimming and snorkeling.
Do you need sun protection in Koh Samui in March?
The average UV index reaches 9 in March in Koh Samui (very high), with about 11.9h of daylight. Protection essential.