Weather in Ko Samui — today
Now in Ko Samui
🌦️
+26°
Drizzle
Feels like +31° · humidity 93%
Today 12.9: +27° / +25°
🕐 13:25
Wind
10 km/h
UV index
7
Air (AQI)
36 · Good
Precipitation
99%
Humidity
93%
Pressure
1010 hPa
Sunrise / sunset
06:10 / 18:22
Sea temperature
🌊 +30°
👕 What to wear today
Warm — a T-shirt and light trousers or shorts.
☂️ Take an umbrellaFeels warmer by 5°
Weather for an activity:
Detailed weather information for Ko Samui
Today, 12 September, Saturday, in Ko Samui (Thailand): cloudy, light rain in places, warm. During the day the air will warm up to +27°, at night around +25°. Due to high humidity it feels like +31°. UV is high (index 7) — sunscreen will come in handy in the sun. Wind up to 13 km/h. High chance of rain — be sure to take an umbrella or a raincoat. Light summer clothing will do — a T-shirt and shorts or light trousers. The sea has warmed up to +30° — great for swimming. The sun will rise at 06:10 and set at 18:22 — daylight lasts 12 hours.Hourly weather in Ko Samui
💧 The bars at the bottom show the hourly precipitation probability. Shaded areas of the chart are the dark hours (before sunrise 🌅 and after sunset 🌇).
Weather in Ko Samui for 14 days
Tap a day to expand it by time of day and open the full forecast. The bar shows the range from the night low (left) to the day high (right).
▶
Today 12.9
🌦️
💧 99%
+25° +27°
Morning
🌦️
+26°
Day
🌦️
+27°
Evening
🌇
+27°
Night
🌙
+25°
▶
Tomorrow 13.9
🌦️
💧 91%
+24° +28°
Morning
🌦️
+26°
Day
🌦️
+28°
Evening
🌇
+27°
Night
🌙
+24°
▶
Mon 14.9
⛈️
💧 86%
+25° +27°
Morning
⛈️
+26°
Day
⛈️
+27°
Evening
🌇
+27°
Night
🌙
+25°
▶
Tue 15.9
⛈️
💧 97%
+25° +29°
Morning
⛈️
+26°
Day
⛈️
+29°
Evening
🌇
+28°
Night
🌙
+25°
▶
Wed 16.9
🌦️
💧 94%
+25° +28°
Morning
🌦️
+26°
Day
🌦️
+28°
Evening
🌇
+27°
Night
🌙
+25°
▶
Thu 17.9
🌦️
💧 94%
+25° +26°
Morning
🌦️
+25°
Day
🌦️
+26°
Evening
🌇
+26°
Night
🌙
+25°
▶
Fri 18.9
🌦️
💧 100%
+25° +26°
Morning
🌦️
+25°
Day
🌦️
+26°
Evening
🌇
+26°
Night
🌙
+25°
▶
Sat 19.9
🌦️
💧 96%
+25° +28°
Morning
🌦️
+26°
Day
🌦️
+28°
Evening
🌇
+27°
Night
🌙
+25°
▶
Sun 20.9
🌦️
💧 96%
+25° +27°
Morning
🌦️
+26°
Day
🌦️
+27°
Evening
🌇
+27°
Night
🌙
+25°
▶
Mon 21.9
🌦️
💧 94%
+25° +29°
Morning
🌦️
+26°
Day
🌦️
+29°
Evening
🌇
+28°
Night
🌙
+25°
▶
Tue 22.9
🌦️
💧 86%
+26° +31°
Morning
🌦️
+28°
Day
🌦️
+31°
Evening
🌇
+30°
Night
🌙
+26°
▶
Wed 23.9
🌦️
💧 86%
+26° +30°
Morning
🌦️
+27°
Day
🌦️
+30°
Evening
🌇
+29°
Night
🌙
+26°
▶
Thu 24.9
🌦️
💧 84%
+26° +30°
Morning
🌦️
+27°
Day
🌦️
+30°
Evening
🌇
+29°
Night
🌙
+26°
▶
Fri 25.9
🌦️
💧 86%
+25° +29°
Morning
🌦️
+26°
Day
🌦️
+29°
Evening
🌇
+28°
Night
🌙
+25°
🗺️ Precipitation radar
Precipitation radar (RainViewer) over a clean base map — updates every 5–10 minutes. Colours show nearby precipitation; if there is none, the map is simply clear — that is normal. Zoom with + / −.
Rain intensity:lightmoderateheavy
🎯 What to do in this weather — indices of the day
Comfort score from 0 (bad) to 100 (excellent), calculated from the day's weather. For “rain” and “UV” a percentage/risk level is shown.
🏖️ Beach
11 / 100
for sea and sun · Bad
🏊 Swimming
0 / 100
water 30° · Bad
🏃 Running
0 / 100
comfort for running · Bad
🧴 UV
63%
high · high
☂️ Rain
99%
likely · high
✨ Stars
19 / 100
evening visibility · Bad
🧺 Laundry drying
0 / 100
will dry outside · Bad
🚗 Car wash
0 / 100
better to wait · Bad
🌫️ Air quality
36
Good air
European AQI
PM2.5: 3PM10: 4O₃: 91NO₂: 1
The air is clean — you can walk and exercise outside.
🌅 Sun, moon and sea
Sunrise
06:10
Sunset
18:22
Golden hour
17:54
Daylight
12 h (-1 min vs yesterday)
Sea temperature
+30°
🌊 calm, waves 0.2 m.
Ko Samui climate by month
Long-term averages. Hover over a bar for details. The forecast for a specific month is a combination of the climate normal and the model forecast for the coming weeks.
+28°
+25°
Jan
+28°
+26°
Feb
+29°
+27°
Mar
+30°
+27°
Apr
+30°
+27°
May
+30°
+27°
Jun
+30°
+27°
Jul
+29°
+27°
Aug
+29°
+26°
Sep
+28°
+26°
Oct
+28°
+26°
Nov
+28°
+26°
Dec
swipe sideways →
Bar color shows temperature:frostcoolcomfortablewarmhot— best months to visit
| Month | Day | Night | Sea | Precipitation | What to pack and what makes the month notable (events, nuances) |
|---|---|---|---|---|---|
| January | +28° | +25° | +28° | 78 mm | Gentle warmth — about +28° daytime, great walking weather. Frequent rain (78 mm over the month) — keep indoor backup plans. 😊 light summer clothing. Water at +28° — great for swimming. This is the coldest month of the year. |
| February | +28° | +26° | +29° | 35 mm | A comfortable month: +28° by day without exhausting heat. 😊 light summer clothing. Water at +29° — great for swimming. Weather-wise, one of the three best months to visit. |
| March | +29° | +27° | +30° | 87 mm | Warm and comfortable: +29° by day, +27° at night. It's a rainy month (87 mm) — an umbrella is a must. 😊 light summer clothing. The sea is +30° — like a warm bath. Weather-wise, one of the three best months to visit. |
| April | +30° | +27° | +32° | 96 mm | Gentle warmth — about +30° daytime, great walking weather. Frequent rain (96 mm over the month) — keep indoor backup plans. 😊 light summer clothing. The sea is +32° — like a warm bath. |
| May | +30° | +27° | +32° | 119 mm | A comfortable month: +30° by day without exhausting heat. One of the wettest months (119 mm): downpours can derail plans. 😊 light summer clothing. The sea is +32° — like a warm bath. This is the hottest month of the year in Ko Samui. |
| June | +30° | +27° | +31° | 93 mm | Warm and comfortable: +30° by day, +27° at night. It's a rainy month (93 mm) — an umbrella is a must. 😊 light summer clothing. The sea is +31° — like a warm bath. The longest daylight hours of the year — more time for everything. |
| July | +30° | +27° | +31° | 88 mm | Gentle warmth — about +30° daytime, great walking weather. Frequent rain (88 mm over the month) — keep indoor backup plans. 😊 light summer clothing. The sea is +31° — like a warm bath. |
| August | +29° | +27° | +31° | 96 mm | A comfortable month: +29° by day without exhausting heat. One of the wettest months (96 mm): downpours can derail plans. 😊 light summer clothing. The sea is +31° — like a warm bath. |
| September | +29° | +26° | +30° | 143 mm | Warm and comfortable: +29° by day, +26° at night. It's a rainy month (143 mm) — an umbrella is a must. 😊 light summer clothing. The sea is +30° — like a warm bath. |
| October | +28° | +26° | +30° | 283 mm | Gentle warmth — about +28° daytime, great walking weather. Frequent rain (283 mm over the month) — keep indoor backup plans. 😊 light summer clothing. The sea is +30° — like a warm bath. Statistically the wettest month of the year. |
| November | +28° | +26° | +29° | 281 mm | A comfortable month: +28° by day without exhausting heat. One of the wettest months (281 mm): downpours can derail plans. 😊 light summer clothing. Water at +29° — great for swimming. |
| December | +28° | +26° | +29° | 144 mm | Warm and comfortable: +28° by day, +26° at night. It's a rainy month (144 mm) — an umbrella is a must. 😊 light summer clothing. Water at +29° — great for swimming. The shortest daylight of the year — it gets dark early. |
When to visit Ko Samui
✅ Recommended time to visit
🌟 Best time: January, February, March
Daytime air+28…+29°
Sea temperature+28…+30°
Precipitationoften
Why: comfortable +28…+29° by day, little rain, warm sea (+28…30°).
⚠️ Doable, with caveats
🌤️ Shoulder season: April, May, June, July, August, December
Daytime air+28…+30°
Sea temperature+29…+32°
Precipitationoften
Why: noticeable rain risk (88–144 mm/month) — pack an umbrella and backup plans.
🔴 Not the best time
🌤️ Shoulder season: September, October, November
Daytime air+28…+29°
Sea temperature+29…+30°
Precipitationoften
Why: the rainy season (143–283 mm/month) — downpours almost daily.
Bottom line: the best time to visit Ko Samui is January – March, and the most comfortable months are January, February, March. The toughest months to visit are September, October, November: frequent rain.
🌡️ Today vs the climate normal
Today's high
+27°
Normal for September
+29°
Deviation
2° colder than normal
A year ago on this day
+31°
Record for this date
+31° (2017)
The normal, “a year ago” and the record come from the weather archive since 1940 (Open-Meteo / ERA5).
Weather archive for Ko Samui
📅 See what the weather was like on any day since 1940. For example: “what was the weather on March 2, 2021”.
Show the archive for the selected day →
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Weather in cities near Ko Samui
Frequently asked questions about the weather in Ko Samui
What is the weather in Ko Samui right now?＋
Drizzle, +26°, feels like +31°.
Will it rain in Ko Samui today?＋
Yes: 99% chance, 26 mm.
When is the best time to visit Ko Samui?＋
Best time to visit — January – March.
Can you swim in Ko Samui in winter?＋
In winter the water is around +29° — great for swimming. In summer the sea warms up to +31°.
What time are sunrise and sunset in Ko Samui?＋
Sunrise 06:10, sunset 18:22.
Does it snow in Ko Samui in winter?＋
No, it practically never snows.
What is the climate in Ko Samui by month?＋
Summers up to +30° in May, winters around +25° in January; the wettest month is October.
How hot is it in Ko Samui in summer?＋
😊 Warm and comfortable. Perfect for walks, the beach and sightseeing.