January – March
Generally considered the best weather of the year with sunshine, calmer seas and comfortable temperatures.
★★★★★ Beach Weather
Koh Samui Weather & Climate Guide
Warm temperatures, tropical sunshine and swimmable seas all year round. Here's what to expect from Koh Samui's weather throughout the seasons.
April – June
The hottest period of the year. Expect long sunny days, warm evenings and ideal swimming conditions.
★★★★☆ Hot & SunnyJuly – September
Generally warm with occasional tropical showers. Plenty of sunshine between passing rain.
★★★☆☆ Mixed ConditionsOctober – December
Samui's wettest period. Rainfall increases but sunny periods are still common between storms.
★★☆☆☆ Green Season
Month By Month
Weather Overview
Month
Conditions
Beach Rating
January
Excellent
★★★★★
February
Excellent
★★★★★
March
Excellent
★★★★★
April
Very Hot
★★★★☆
May
Hot & Sunny
★★★★☆
June
Warm
★★★★☆
July
Mixed
★★★☆☆
August
Mixed
★★★☆☆
September
Mixed
★★★☆☆
October
Wet
★★☆☆☆
November
Wettest
★☆☆☆☆
December
Improving
★★★☆☆
28–32°C
Average daytime temperatures
28–30°C
Sea temperature year-round
365 Days
Warm enough to swim every month
Year Round
Tropical climate and sunshine
Best Time To Visit Koh Samui
December – April
Generally offers the best beach weather, calm seas and plenty of sunshine.
May – September
Excellent for visitors seeking fewer crowds, good weather and better accommodation deals.
October – November
The green season brings heavier rainfall but also lush landscapes and quieter beaches.
