Koh Samui Climate and Average Weather
Climate of Koh Samui: average temperatures, rainfall and seasons month by month.
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).
Recent extremes in Koh Samui
Highest and lowest readings observed in the last 3 years of reanalysis data - not all-time records.
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 |
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 this means for Koh Samui
Today is about average for August. The forecast high of 85°F is in line with the 84°F typical for this month.
A 41% chance means rain is likely somewhere nearby at some point - carry a layer, but do not cancel.
Gusts to 31 mph will push high-sided vehicles on exposed roads and bridges.
Within 15 degrees of the equator, day length barely changes all year; seasons are defined by rain, not temperature.
Northern Hemisphere, so peak summer falls in June to August.
The gap between the warmest and coldest month averages 37°F - an unusually even climate through the year.
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 31 mph.
- If your dates are flexible, avoid October, November and December - historically the least comfortable months here.
Summary
Koh Samui is an island in Thailand. Koh Samui is an island known for palm-fringed beaches in the Gulf.
Right now it is 80°F (27°C) in Koh Samui with overcast. It feels like 86°F. Today runs from 75°F to 85°F. Chance of precipitation is 41%. Sightseeing conditions score 8.4/10 - good conditions.
The best time to visit Koh Samui is January, February, March and April. The climate is temperate. October, November and December tend to be the least comfortable months. April is the warmest month with average highs near 86°F, while January is the coldest with lows near 72°F.
The closest major airport is Phuket International Airport (HKT), about 151 mi away. Nearby highlights include Khao Sok National Park, Railay Beach, Maya Bay and Phuket.
In plain terms. Today is about average for August. The forecast high of 85°F is in line with the 84°F typical for this month. The best window to be outside is roughly 7 AM to 10 AM, when temperature, rain chance and wind line up best. fishing is the strongest bet in Koh Samui today at 9/10. Gusts to 31 mph will push high-sided vehicles on exposed roads and bridges.
Compiled from this page's own data: atlas facts plus live Open-Meteo readings.
Quick facts about Koh Samui
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.
Explore Koh Samui
Every topic we hold for this place, and the same topic for the places around it.
Climate 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 (27°C) with overcast. Humidity is 76% and wind is 8 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 9:36 PM.
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 23, 2026 at 9:36 PM local time. Live blocks refresh every 15 minutes; climate averages monthly.
