Koh Samui Weather Forecast
Koh Samui weather: 80°F, overcast. Hourly forecast, 14-day outlook, UV, air quality and the best time to visit.
Koh Samui weather in May
Weather map for Koh Samui
Animated model layers. Pick a layer to load it.
Animated layers by Windy. For pin-level detail and nearby places, see the interactive map below.
Climate in Koh Samui month by month
Average high, average low and total rainfall, based on three years of reanalysis data.
| Month | Avg high | Avg low | Rainfall | Rating |
|---|---|---|---|---|
| January | 79° | 72° | 2,3 in | ★★★★☆ |
| February | 81° | 73° | 2,6 in | ★★★★☆ |
| March | 83° | 74° | 1,3 in | ★★★★★ |
| April | 86° | 76° | 1,9 in | ★★★★☆ |
| May | 85° | 75° | 5,5 in | ★★★★☆ |
| June | 86° | 75° | 3,3 in | ★★★★☆ |
| July | 85° | 75° | 4,1 in | ★★★★☆ |
| August | 84° | 74° | 3,8 in | ★★★★☆ |
| September | 82° | 74° | 5,0 in | ★★★★☆ |
| October | 81° | 73° | 9,3 in | ★★★☆☆ |
| November | 79° | 72° | 11,9 in | ★★★☆☆ |
| December | 79° | 72° | 7,2 in | ★★★☆☆ |
Climate type: Temperate. Source: Open-Meteo archive (ERA5).
Best time to visit Koh Samui
Go in January, February, March and April. These months score highest on comfortable temperatures, low rainfall and useful daylight.
Hardest months: October, November and December - expect the least comfortable mix of heat, cold or rain.
What to pack, what to skip
- Lightweight, light-coloured clothing and a refillable water bottle
- Sunglasses, a brimmed hat and SPF 30+
- A packable rain shell - 7 of the next 7 days carry a real chance of rain
- Avoid exposed ridgelines, small boats and rooftop viewpoints while gusts stay above 39 mph.
- If your dates are flexible, avoid October, November and December - historically the least comfortable months here.
How Koh Samui compares with nearby places
Annual averages, and the difference against Koh Samui.
| Place | Distance | Avg temp | vs here | Annual rain |
|---|---|---|---|---|
| Khao Sok National Park | 110 mi | 79°F | +34°F warmer | 108 in |
| Railay Beach | 131 mi | 81°F | +36°F warmer | 84 in |
| Phuket International Airport | 151 mi | 82°F | +36°F warmer | 90 in |
| Maya Bay | 153 mi | 83°F | +37°F warmer | 81 in |
| Phuket | 158 mi | 82°F | +36°F warmer | 81 in |
See the Koh Samui forecast by time range
Koh Samui weather - more answers
Explore Koh Samui
Every topic we hold for this place, and the same topic for the places around it.
Weather for related places
Frequently asked questions
Where is Koh Samui?
Koh Samui is an island in Thailand. Its coordinates are 9.512, 100.0136. It lies in Asia.
What is the weather like in Koh Samui right now?
It is currently 80°F (26°C) with overcast. Humidity is 74% and wind is 11 mph.
When is the best time to visit Koh Samui?
January, February, March and April offer the most comfortable conditions in Koh Samui, which has a temperate climate. October, November and December are usually the hardest months for outdoor plans.
What time zone is Koh Samui in?
Koh Samui observes Asia/Bangkok (UTC+07:00). The local time is 10:34 AM.
What is the nearest airport to Koh Samui?
The closest airports are Phuket International Airport (HKT), 151 mi away and Suvarnabhumi Airport (BKK), 293 mi away.
What are the top things to do in Koh Samui?
Popular options include Khao Sok National Park, Railay Beach, Maya Bay, Phuket and Langkawi.
Related articles
Data sources and methodology
| Place data | USPOTUS Atlas dataset (islands) - coordinates, hierarchy and facts. |
|---|---|
| Forecast and observations | Open-Meteo (ECMWF and national models). |
| Air quality and pollen | Copernicus CAMS via Open-Meteo. US AQI scale. |
| Climate averages | ERA5 reanalysis via the Open-Meteo archive, aggregated over 3 years. |
| Method | Scores, comparisons and advice on this page are computed from the inputs above. Distances are straight-line. Nothing is estimated where data is missing - the block is simply not shown. |
Last updated August 26, 2026 at 10:34 AM local time. Live blocks refresh every 15 minutes; climate averages monthly.
