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Koh Samui, Thailand · Equatorial tropical

Koh Samui in August: go or not?

Mixed period. Koh Samui in August: 5.2/10.

📅 Data updated: October 2026 🛰️ ERA5 · 10 years 📍 9.51°N · 100.06°E
⚡ This month's verdict
Why not
Koh Samui · August
5.2
26–31°
Temperature
34%
Rain
5h
Sun
🌴 Tropical☀️ High UV🌧️ Monsoon season
Photo : RODOLFO BARRETTO via Unsplash
The month in detail

What to expect in August

In August, Koh Samui sees 31°C during the day with 4.9h of sunshine per day. Expect rain on 34% of days — a light raincoat in the bag is recommended.

August ranks 6 out of 12 months in Koh Samui.

This month's conditions

What it's like in August

UV index
8 · very high
protection essential
Feels like
very humid
23°
Sea
30°C
warm, ideal
Daylight
12.3h of daylight
Air quality
good
AQI 21
Compare

Is August the right month?

The best month in Koh Samui is February (6.0/10), 0.8 pt higher than August.

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 August?
In August, the sea averages 30°C in Koh Samui: warm, ideal. Ideal conditions for swimming and snorkeling.
Do you need sun protection in Koh Samui in August?
The average UV index reaches 8 in August in Koh Samui (very high), with about 12.3h of daylight. Protection essential.