Warm
Average highs sit around 30°C, giving warm days by monthly-average standards.
Weather Guide
Koh Samui, Thailand Average Monthly Weather
Weather score65Good annual avg
Best months: February, March, January
Across the year, average daytime temperatures are around 30°C, sunshine averages 6.5h per day, and rainfall totals about 1941mm. Sea temperatures average 29°C across the year.
Annual weather
Annual averages
Temp
30°C
Rain
1941mm
Annual total
Sun
6.5h
Sea
29°C
Weather score
65
Good avg
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
SwimSwim
Weather scoreWeather score
Trip feel
Wet
Rainfall averages 275mm, so showers are a real planning factor.
Some sun
Sunshine averages 5.7h per day, enough for a balanced month.
Warm sea
Sea temperatures average 29°C, so swimming is usually comfortable by monthly-average standards.
Map
Weather map
Compare Koh Samui, Thailand with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
October30°C average high
October is close to Koh Samui's yearly temperature average, giving a typical read on daytime heat.
Warmest monthsApril to September
This stretch sets the upper range for average daytime heat.
Rain
October275mm average rain
October sits near Koh Samui's yearly rainfall average, so rain is a normal planning factor rather than an outlier.
Driest monthsJanuary to September
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
October5.7 hours average sun
October is one of Koh Samui's cloudier months, so sunshine-led plans are less reliable.
Brightest monthsFebruary to April
This stretch has the strongest sunshine in the monthly averages.
Sea temperature
October29°C average sea
October is close to Koh Samui's yearly sea-temperature average, so swimming comfort is fairly typical.
Warmest seaApril to September
Sea temperatures are usually near 30°C in this stretch, so swimming comfort is at its strongest.
Weather score
October52 weather score
October is one of the weakest weather-score months, when the overall mix is less favourable than the rest of the year.
Best weather monthsFebruary to March
These months have the strongest weather score in the monthly averages.
