Thailand Koh Samui Weather in April — Climate Guide
April in Koh Samui is high
Koh Samui Weather in April — Quick Answer
As of 2026- Avg temp
- 32° / 25°
- Rainfall
- 100mm · 9 days
- Crowds
- Busy
As of 2026, Koh Samui in April averages a high of 32°C and low of 25°C with 100mm of rain over about 9 days. Hottest month of the year — around 32°C/25°C, hot and increasingly humid with the odd afternoon shower. Light clothing, swimwear, a hat, SPF 50+, and plenty of water. Extreme UV. Sea ~30°C.
April is high for Koh Samui.
April is Koh Samui's hottest month and the tail of the dry season, averaging 32°C/25°C with rainfall starting to creep up (around 100mm) as the odd afternoon shower returns.
The headline event is Songkran (Apr 13-15), the Thai New Year — a nationwide water festival of street water fights and temple visits. It's a fun, soaking experience in Chaweng, Lamai, and Bophut; keep your phone in a waterproof pouch and expect everything to be wetter than planned.
Travel score
Koh Samui April Weather Stats
Avg High
32°C
Avg Low
25°C
Rainy Days
9
100mm total
Sunshine
8.5h
Daily avg
Humidity
78%
muggy
UV Index
12
Extreme
Wind
11 km/h
Gusts 20
Sea Temp
30°C
Avg water temp
Crowds
Busy
At attractions
April Sunrise & Sunset
Air Quality
PM2.5
16 μg/m³
PM10
30 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
11 km/h
Max gust 20 km/h
Activities Recommended for April
April Travel Pros & Cons
Pros
- Songkran water festival (Apr 13-15) — a fun cultural highlight
- Still mostly dry and good for boat trips early-mid month
- Hot, sunny beach weather
- Warm sea (~30°C)
Cons
- Hottest month — intense heat and extreme UV (12)
- Afternoon showers begin late month
- Songkran means you'll get soaked everywhere
- Higher prices and crowds
April Events & Festivals
- Songkran — Thai New Year water festival (Apr 13-15)
- Hottest month of the year
- End of the dry season — occasional afternoon showers start
- Still good for boat trips early-to-mid month
Koh Samui in April — Full Picture
April is Koh Samui's hottest month and the tail of the dry season, averaging 32°C/25°C with rainfall starting to creep up (around 100mm) as the odd afternoon shower returns.
The headline event is Songkran (Apr 13-15), the Thai New Year — a nationwide water festival of street water fights and temple visits. It's a fun, soaking experience in Chaweng, Lamai, and Bophut; keep your phone in a waterproof pouch and expect everything to be wetter than planned.
Early-to-mid April still has good, mostly dry weather and calm seas for Ang Thong and Koh Tao trips, but the heat is intense and humidity climbs toward the May wet season. UV is extreme (12) — this is the month to be most careful with sun and hydration.
It remains a busy, higher-priced month thanks to Songkran and the dry season's end. The sea warms to about 30°C.
After April, Samui shifts toward its long wet season (with a drier June-August spell) — the opposite pattern to the Andaman coast, which is heading into its rainy months.
What to Wear & What to Pack
Hottest month of the year — around 32°C/25°C, hot and increasingly humid with the odd afternoon shower. Light clothing, swimwear, a hat, SPF 50+, and plenty of water. Extreme UV. Sea ~30°C.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
Current31.7°C
25°C
10/mo
Summer (Jun·Jul·Aug)
32°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 April Hotel Picks
Frequently Asked Questions
Is April a good time to visit Koh Samui?
Koh Samui in April is high. Tourist crowds are busy and flight/hotel prices are peak.
What's the average temperature in Koh Samui in April?
Koh Samui April averages a high of 32°C and a low of 25°C.
Does it rain much in Koh Samui in April?
Koh Samui April averages 100mm of rainfall over about 9 rainy days.
What should I wear in Koh Samui in April?
Hottest month of the year — around 32°C/25°C, hot and increasingly humid with the odd afternoon shower. Light clothing, swimwear, a hat, SPF 50+, and plenty of water. Extreme UV. Sea ~30°C.
What time are sunrise and sunset in Koh Samui in April?
Koh Samui April sunrise is 06:05 and sunset is 18:25, with 12h 20min of daylight.
What's the air quality like in Koh Samui in April?
Koh Samui April air quality (AQI) averages 42, rated Good. PM2.5 averages 16μg/m³.
What activities are recommended in Koh Samui in April?
In April, Koh Samui is great for Songkran water festival in Chaweng/Lamai, Ang Thong & Koh Tao (early-mid month), Beach days (mind the heat).
Is April peak season in Koh Samui?
Koh Samui April crowds are busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit Koh Samui
View Other Months
Planning a April 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.