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Koh Samui, Thailand · Equatorial tropical

Koh Samui: best months to visit

February (6.0/10) · October (4.9/10).

📅 Data updated: October 2026 🛰️ ERA5 · 10 years 📍 9.51°N · 100.06°E
⚡ Quick answer
February
Depends on your goals
6.0/10
☀️ Feb
Top score (6.0/10)
🌤️ Mar
Alt. (5.9/10)
Oct
Plus rude (4.9/10)
🌴 Tropical☀️ High UV🌧️ Monsoon season
Photo par RODOLFO BARRETTO via Unsplash
Decide

When to visit Koh Samui?

The decision rests on several criteria. Climate score, tourist crowds and feasible activities.

Verdict: In Koh Samui, February and March clearly stand out. October concentrates the least favourable conditions.
Top & avoid
🏆 February · 6.0 March · 5.9 January · 5.7 April · 5.6 ⚠️ October · 4.9
5.7
Jan
6.0
Feb
5.9
Mar
5.6
Apr
5.2
May
5.1
Jun
5.1
Jul
5.2
Aug
5.1
Sep
4.9
Oct
5.0
Nov
5.3
Dec
Best period · ≥ 7 Decent period · 4 – 7 Tough conditions · < 4

What you grasp in 5 seconds

Koh Samui offers 0 comfortable months, without any month really to avoid. The gap stays moderate: 6.0 in February vs 4.9 in October.

What to check next

Your tolerance for crowds and budget. The best months concentrate tourist saturation and higher prices. Shoulder seasons offer a good compromise.

Next action

Scroll down to the detailed table to compare month by month, then open the page of the month that interests you.

Compare the 12 months By your project

How we calculate the score

The score combines 4 weighted criteria using 10 years of real climate data (ERA5).

Source : ERA5 · Open-Meteo · 10 years (2016–2025) · Full methodology →

Understand

Compare all 12 months

Month-by-month details: temperature, rain, sunshine, score and verdict.

✅ 0 comfortable months ()
MonthT° minT° maxRain %mm/daySunScoreVerdict
🌥️ January →24°C28°C27%4.3mm6.4h5.7/10Decent period
⛅ February →25°C29°C15%2.1mm7.6h6.0/10Decent period
🌥️ March →26°C30°C15%1.4mm7.7h5.9/10Decent period
🌥️ April →26°C31°C20%3.6mm6.7h5.6/10Decent period
🌥️ May →26°C31°C35%3.8mm6.2h5.2/10Decent period
🌥️ June →26°C31°C34%2.5mm5.0h5.1/10Decent period
🌥️ July →26°C31°C35%3.2mm5.0h5.1/10Decent period
🌥️ August →26°C31°C34%2.7mm4.9h5.2/10Decent period
🌥️ September →26°C30°C35%4.4mm4.8h5.1/10Decent period
🌥️ October →25°C29°C51%7.3mm4.7h4.9/10Decent period
🌥️ November →25°C28°C55%9.5mm5.8h5.0/10Decent period
🌥️ December →24°C28°C37%7.2mm5.7h5.3/10Decent period
🌥️ January
5.7/10
T°24°C / 28°C
Rain %27%
Sun6.4h
Decent period
⛅ February
6.0/10
T°25°C / 29°C
Rain %15%
Sun7.6h
Decent period
🌥️ March
5.9/10
T°26°C / 30°C
Rain %15%
Sun7.7h
Decent period
🌥️ April
5.6/10
T°26°C / 31°C
Rain %20%
Sun6.7h
Decent period
🌥️ May
5.2/10
T°26°C / 31°C
Rain %35%
Sun6.2h
Decent period
🌥️ June
5.1/10
T°26°C / 31°C
Rain %34%
Sun5.0h
Decent period
🌥️ July
5.1/10
T°26°C / 31°C
Rain %35%
Sun5.0h
Decent period
🌥️ August
5.2/10
T°26°C / 31°C
Rain %34%
Sun4.9h
Decent period
🌥️ September
5.1/10
T°26°C / 30°C
Rain %35%
Sun4.8h
Decent period
🌥️ October
4.9/10
T°25°C / 29°C
Rain %51%
Sun4.7h
Decent period
🌥️ November
5.0/10
T°25°C / 28°C
Rain %55%
Sun5.8h
Decent period
🌥️ December
5.3/10
T°24°C / 28°C
Rain %37%
Sun5.7h
Decent period
📊 Quick read
Optimal window
No month > 7
Good transition
—
Tough period
none
🌡️ Detailed conditions (February)
🌡️ Feel
Humid heat
☀️ UV
8.6 · Very strong
💧 Humidity feel
22°C · Oppressive
☔ Rain
15% · 2.1 mm/day
🌅 Sunshine
7.6h/day
Week by week

Koh Samui week by week: your odds of avoiding rain

For each week of the year: in how many years out of 10 it was mostly dry (at most 2 rainy days), 2016 to 2025.

Safest week: Mar 12 to Mar 18, mostly dry in 10 years out of 10 (0.6 rainy day(s) on average).

Most exposed: Nov 5 to Nov 11, mostly dry in 2 years out of 10 (4.0 rainy days on average).

Number = years out of 10 with at most 2 rainy days in the week. Source: ERA5 reanalysis (ECMWF) via Open-Meteo, daily data 2016-2025. Rainy day = at least 1 mm, as everywhere on the site.
JanJan 16/1028°CJan 89/1028°CJan 158/1028°CJan 226/1028°CJan 2910/1028°C
FebFeb 59/1029°CFeb 129/1029°CFeb 197/1029°CFeb 269/1029°C
MarMar 58/1030°CMar 1210/1030°CMar 199/1030°CMar 269/1031°C
AprApr 26/1030°CApr 99/1031°CApr 168/1031°CApr 238/1031°CApr 306/1031°C
MayMay 76/1031°CMay 145/1031°CMay 218/1031°CMay 283/1031°C
JunJun 45/1031°CJun 117/1032°CJun 184/1031°CJun 254/1031°C
JulJul 26/1031°CJul 95/1030°CJul 166/1031°CJul 234/1031°CJul 306/1031°C
AugAug 67/1031°CAug 136/1031°CAug 204/1031°CAug 274/1030°C
SepSep 36/1030°CSep 103/1030°CSep 174/1030°CSep 242/1030°C
OctOct 14/1029°COct 82/1029°COct 152/1029°COct 224/1028°COct 293/1028°C
NovNov 52/1028°CNov 125/1028°CNov 192/1028°CNov 262/1028°C
DecDec 34/1028°CDec 105/1028°CDec 177/1028°CDec 243/1028°C

A specific date? The app computes the same figure day by day.

10-year trend

Annual temperatures — Koh Samui

Min/max temperature curves observed over the past 10 years (ERA5). Shows climate stability and trend.

T° maxT° meanT° min24°26°28°30°32°201620172018201920202021202220232024202530.4° — decade peak (2024)+0.20°C / decade
Tailor

For your trip

A few angles depending on what kind of trip you are planning.

🌞 Dry season🏖️ Beaches🌊 Surf
Book

Plan your trip

Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.

🏨
Stay
Hotels & rentals · Koh Samui
Expedia →
🎟️
Activities
Tours, tickets, experiences
See ↓
✈️
Flights
Multi-airline comparator
Kiwi →

🎟️ Activities & tours · Koh Samui

GetYourGuide selection · free cancellation

See all →
Affiliate link · GetYourGuide
Practical info

What you need to know before you go

Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a tropical stay.

Country · Thailand

🗣️LanguageThai
💶CurrencyThai Baht (฿)
🚗DrivingLeft-hand
🛡️Safety ⓘSafe · 2/5
💰Cost of living ⓘCheap · 2/5

🌡️ Climate

🌍Climate typeEquatorial tropical
📈Climate trend ⓘStable
🔥Hottest monthApril · 31°C
❄️Coolest monthJanuary · 28°C
🌧️Rainiest month ⓘNovember · 55%

🏝️ Tropical stay

🌞Dry season ⓘMay → Sep
🌧️Wet season ⓘDec → Mar
🌀Cyclones ⓘNone (equator)
Explore

Related destinations & guides

If this destination doesn't fit your dates, here are alternatives and guides.

Similar climate destinations

Providencia · Colombia→Kota Kinabalu · Malaysia→Koh Tao · Thailand→Hue · Vietnam→

Nearby destinations

Krabi · Thailand202 km →Koh Phi Phi · Thailand242 km →Koh Lanta · Thailand247 km →Phuket · Thailand258 km →

Guides & rankings

World ranking 2026See →
Best summer destinationsSee →
Winter sunSee →
Where to go in JulySee →
Location

Where is Koh Samui ?

Global position + regional geographic context.

🌍 World
🔍 Geographic context
Equatorial tropical climate with a 6.0 → 4.9 gap between best and worst month. 10 years of ERA5 data to choose by project.
9.51°N · 100.06°E
Questions

Frequently asked questions

What is the best time to visit Koh Samui?
February is the best month with 29.0°C highs, 25.0°C lows, 7.6h of sunshine and 15.0% rainy days.
How many hours of sunshine does Koh Samui get in February?
Koh Samui averages 7.6 sunshine hours per day in February. It is the sunniest month with a climate score of 5.9/10.
What is the rainiest month in Koh Samui?
October is the most unfavourable month with October has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Koh Samui in February?
In February, overnight lows reach 25.0°C, while afternoon highs average 29.0°C.
Is Koh Samui good in winter?
In winter (December-February), Koh Samui scores 5.5/10 on average — Decent period conditions for cultural visits.. The best month overall remains February with a score of 5.9/10.
When should you avoid Koh Samui?
October is the most difficult month to visit Koh Samui, with October has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.