Monthly weather overview

iconKo Samui monthly weather overview Thailand · 코사무이

A quick, year-round overview of monthly and seasonal weather in Ko Samui. Use this page to get a feel for which months and seasons match your travel style.

Koh Samui weather at a glance

  • Koh Samui is a Gulf-of-Thailand island: warm and humid most of the year. Comfort is often shaped by humidity, short intense showers, sea conditions (wind/waves), and strong indoor AC.
  • Many travelers feel the pattern as: relatively drier months (Jan–Apr), more frequent showers (May–Sep), and a wetter peak that can feel stronger around Oct–Dec. Rainy-season timing can differ from the Andaman side, so “monsoon” can feel different by region.
  • Boat and snorkeling plans depend not only on rain but also on wind, waves, and visibility. Treat them as conditional and keep a backup plan.
  • Resorts and cafés can run strong AC, creating hot-outside / cool-inside contrast—one thin layer helps.
  • When it rains, slick roads and puddles matter. Managing dampness (drying off quickly) often decides comfort.
Jan · Feb · Mar · Apr

Relatively drier season: more open-sky days and steadier beach pacing

Avg low 24–26°C / high 30–33°C · Rainy days: 3–10 / 30–120 mm (varies by month)

  • Humidity can feel lower and less sticky on many days.
  • Beach and boat plans tend to run more smoothly.
  • Strong midday sun still makes exposure time a key variable.

Suggested outfits

  • · Breathable summer clothing
  • · Quick-dry beachwear
  • · Thin layer for indoor AC

A note for travelers

Even in drier months, shade and planned breaks often decide comfort.

May · Jun · Jul · Aug · Sep

Showers + humidity season: bursty rain and sticky air

Avg low 25–26°C / high 30–32°C · Rainy days: 10–20 / 90–220 mm

  • Short intense showers can pause movement and soak clothes quickly.
  • High humidity can make heat feel heavier.
  • After rain, it turns hot again—staying damp gets uncomfortable.

Suggested outfits

  • · Quick-dry fabrics
  • · Water-safe pouch/rain jacket option
  • · Wet-tolerant shoes with grip

A note for travelers

This season often works best with a pause-and-move rhythm.

Oct · Nov · Dec

Wetter peak months: higher rain frequency/intensity on many days

Avg low 24–26°C / high 29–31°C · Rainy days: 15–25 / 180–450 mm (often peaking around Nov)

  • Repeated rain can interrupt transfers more often.
  • Sea conditions can be more volatile, affecting boat schedules.
  • Indoor anchors (resort/café/spa) reduce stress.

Suggested outfits

  • · Quick-dry fabrics
  • · Water-safe pouch
  • · Less-slippery footwear

A note for travelers

Oct–Dec is much easier with strong backup plans.

Want detailed monthly weather?

Pick a month below to see detailed average temperatures, rainfall, outfit ideas, and travel tips.

Explore Ko Samui

These pages are connected so you can compare conditions and decide for yourself.

Ko Samui monthly weather overview — seasons & best time to visit | CityWeather | CityWeather