Koh Samui in August
In August, Koh Samui averages 30°C (86°F) during the day and 26°C (79°F) at night, with frequent rain — about 28 days of the month see precipitation (94 mm total).
High seasonConditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.
August offers comfortable temperatures in Koh Samui, with some rain to plan around.
How August compares to the rest of the year in Koh Samui
August is in the middle of the year for warmth in Koh Samui (6th of 12) and moderately rainy compared to the rest of the year (6th of 12). Daytime temperature runs 1°C above the annual average (29°C). August runs roughly the same as July (30°C) and cools 1°C in September (29°C).
August sunrise & sunset in Koh Samui
Times shown for Koh Samui local time (Asia/Bangkok), calculated for the 15th of August. They shift by a few minutes day to day across the month.
Photography light in Koh Samui — August
Golden-hour and blue-hour windows for the 15th of August, in Koh Samui's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Koh Samui in August
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on August's tier (High season) and Koh Samui's popularity.
Crowds & pricing — August in Koh Samui
This is a busy month in Koh Samui — not the absolute peak, but tourist numbers are clearly elevated. You'll feel it at headline attractions on weekends and in the historic centre, though side streets and lesser-known sights stay manageable. Prices are above off-season but not at their summit. A good week for first-time visitors who want everything open without the worst of the crush.
Why this tier: Northern Hemisphere summer holidays
Sun & mosquito risk — August in Koh Samui
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Sea temperature in Koh Samui — August
Across the year Koh Samui's sea swings from 28.6°C (January) to 32.1°C (May) — August sits at 30.7°C.
Koh Samui in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 28°C / 82°F | 25°C / 76°F | 113 mm | 24 | — |
| February | 28°C / 83°F | 25°C / 77°F | 33 mm | 17 | — |
| March | 30°C / 86°F | 26°C / 78°F | 32 mm | 17 | — |
| April | 31°C / 87°F | 27°C / 80°F | 107 mm | 23 | — |
| May | 31°C / 87°F | 27°C / 80°F | 130 mm | 29 | — |
| June | 30°C / 86°F | 27°C / 80°F | 96 mm | 27 | — |
| July | 30°C / 86°F | 26°C / 79°F | 115 mm | 28 | — |
| August | 30°C / 86°F | 26°C / 79°F | 94 mm | 28 | — |
| September | 29°C / 84°F | 26°C / 78°F | 172 mm | 29 | — |
| October | 28°C / 83°F | 25°C / 77°F | 234 mm | 31 | — |
| November | 28°C / 82°F | 25°C / 77°F | 274 mm | 29 | — |
| December | 28°C / 82°F | 25°C / 76°F | 182 mm | 24 | — |
Other cities with similar August weather
🌍 See the full ranked list of climate twins for Koh Samui in August →
Frequently asked questions
How hot is Koh Samui in August?
In August, Koh Samui averages a high of 30°C (86°F) and a low of 26°C (79°F) — generally hot.
Does it rain a lot in Koh Samui in August?
August is quite rainy in Koh Samui, with about 28 rainy days on average.
Is August a good time to visit Koh Samui?
August is hot but on the rainy side. It suits travelers who are comfortable with hot weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Koh Samui in August?
Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full August packing list for Koh Samui for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.