Thailand Koh Samui Weather in August — Climate Guide
August in Koh Samui is high
Koh Samui Weather in August — Quick Answer
As of 2026- Avg temp
- 32° / 25°
- Rainfall
- 110mm · 14 days
- Crowds
- Very busy
As of 2026, Koh Samui in August averages a high of 32°C and low of 25°C with 110mm of rain over about 14 days. Last of the drier mid-year spell — warm, often sunny, with passing showers. Around 32°C/25°C. Light clothing, swimwear, SPF 50+, and a light rain layer. Sea ~30°C.
August is high for Koh Samui.
August closes Koh Samui's drier mid-year window, averaging 32°C/25°C with modest rainfall (around 110mm). It's still one of the better months, though rainfall starts to edge up toward the autumn wet peak.
Weather is generally good — sunny stretches with passing showers, and mostly calm seas for Ang Thong, Koh Phangan, and Koh Tao trips. As European school holidays continue, it remains high season with busy beaches and higher prices; book ahead.
Travel score
Koh Samui August Weather Stats
Avg High
32°C
Avg Low
25°C
Rainy Days
14
110mm total
Sunshine
7h
Daily avg
Humidity
78%
muggy
UV Index
11
Extreme
Wind
12 km/h
Gusts 22
Sea Temp
30°C
Avg water temp
Crowds
Very busy
At attractions
August Sunrise & Sunset
Air Quality
PM2.5
14 μg/m³
PM10
26 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
38°C
Nighttime
27°C
Humidity and wind affect how the actual temperature feels.
Wind
12 km/h
Max gust 22 km/h
Activities Recommended for August
August Travel Pros & Cons
Pros
- Last of the reliable mid-year window
- Generally sunny with calm seas
- Good for boat trips and diving
- Still better than the rainy Andaman coast
Cons
- European summer high season — busy and pricier
- Rainfall edging up late month
- High humidity
- Passing showers possible
August Events & Festivals
- End of the drier mid-year window (Jun-Aug)
- European summer-holiday high season continues
- Generally good boat-trip conditions
- Mother's Day / Queen's Birthday (Aug 12) — Thai public holiday
Koh Samui in August — Full Picture
August closes Koh Samui's drier mid-year window, averaging 32°C/25°C with modest rainfall (around 110mm). It's still one of the better months, though rainfall starts to edge up toward the autumn wet peak.
Weather is generally good — sunny stretches with passing showers, and mostly calm seas for Ang Thong, Koh Phangan, and Koh Tao trips. As European school holidays continue, it remains high season with busy beaches and higher prices; book ahead.
The Gulf timing still favors Samui: the Andaman coast (Phuket/Krabi) is in its rainy season while Samui enjoys a generally drier spell — though that advantage starts narrowing as both coasts head toward the wettest part of the year for Samui (Oct-Dec).
The sea is warm (~30°C) and good for water activities. UV remains high (11).
From September the rains build, so August is the last of the dependable mid-year months before Samui's wet peak.
What to Wear & What to Pack
Last of the drier mid-year spell — warm, often sunny, with passing showers. Around 32°C/25°C. Light clothing, swimwear, SPF 50+, and a light rain layer. Sea ~30°C.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
31.7°C
25°C
10/mo
Summer (Jun·Jul·Aug)
Current32°C
25°C
13.3/mo
Autumn (Sep·Oct·Nov)
30°C
24.3°C
18/mo
Winter (Dec·Jan·Feb)
29°C
24°C
12.3/mo
Koh Samui Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 29° | 24° | 14d·180mm | 6.5h | 82% | 10 | Very busy | Peak | |
| February (Best) | 30° | 24° | 6d·60mm | 8h | 78% | 11 | Very busy | Peak |
| March (Best) | 31° | 25° | 7d·75mm | 8.5h | 78% | 12 | Busy | Peak |
| 32° | 25° | 9d·100mm | 8.5h | 78% | 12 | Busy | Peak | |
| 32° | 25° | 14d·150mm | 7h | 80% | 11 | Moderate | Shoulder | |
| 32° | 25° | 13d·110mm | 7.5h | 78% | 11 | Busy | Shoulder | |
| 32° | 25° | 13d·110mm | 7.5h | 78% | 11 | Very busy | Peak | |
| 32° | 25° | 14d·110mm | 7h | 78% | 11 | Very busy | Peak | |
| 31° | 25° | 15d·150mm | 6h | 80% | 10 | Moderate | Shoulder | |
| 30° | 24° | 19d·290mm | 5h | 84% | 9 | Quiet | Low season | |
| 29° | 24° | 20d·340mm | 4.5h | 85% | 9 | Quiet | Low season | |
| 28° | 24° | 17d·230mm | 5h | 84% | 9 | Very busy | Peak |
View Other Months
Koh Samui August Hotel Picks
Frequently Asked Questions
Is August a good time to visit Koh Samui?
Koh Samui in August is high. Tourist crowds are very busy and flight/hotel prices are peak.
What's the average temperature in Koh Samui in August?
Koh Samui August averages a high of 32°C and a low of 25°C.
Does it rain much in Koh Samui in August?
Koh Samui August averages 110mm of rainfall over about 14 rainy days.
What should I wear in Koh Samui in August?
Last of the drier mid-year spell — warm, often sunny, with passing showers. Around 32°C/25°C. Light clothing, swimwear, SPF 50+, and a light rain layer. Sea ~30°C.
What time are sunrise and sunset in Koh Samui in August?
Koh Samui August sunrise is 06:05 and sunset is 18:30, with 12h 25min of daylight.
What's the air quality like in Koh Samui in August?
Koh Samui August air quality (AQI) averages 38, rated Good. PM2.5 averages 14μg/m³.
What activities are recommended in Koh Samui in August?
In August, Koh Samui is great for Ang Thong Marine Park (good conditions), Koh Tao diving & snorkeling, Beach days + island loop.
Is August peak season in Koh Samui?
Koh Samui August crowds are very busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit Koh Samui
View Other Months
Planning a August trip to Koh Samui?
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Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.