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Koh Samui Rainfall & Precipitation: Monthly Averages and Year-Round Insights

This page shows the average amount of rainfall per month in Koh Samui. The numbers are calculated over a 30-year period to provide a reliable average. Now, let’s explore all the details to give you a full picture.

Koh Samui experiences significant rainfall throughout the year, averaging 1645 mm of precipitation annually.

Monthly Precipitation Levels

The average number of days each month with precipitation (> 0.2 mm)

Significant seasonal changes in precipitation occur throughout the year. During the wet season, October receives substantial rainfall, averaging 296 mm of precipitation, recorded across 20 rainy days.

In contrast, the drier season, February brings less rainfall, with 44 mm over 5 rainy days.

October, the wettest month, has a maximum daytime temperature of 29°C. The city receives 146 hours of sunshine in this period. During the driest month February you can expect a temperature of 29°C. For more detailed insights into the city’s temperatures, visit our Koh Samui Temperature page.

Annual Precipitation in Thailand

The map below shows the annual precipitation across Thailand. You can also select the different months in case you are interested in a specific month.

Annual
Map not visible? Whoops sorry! Please refresh the page.
Legend heavy rainfall high moderate low almost none
Heavy annual rainfall has been defined as more than 1000 mm precipitation. High: 600 mm to 1000 mm. Moderate: 250 mm to 600 mm. Low: less than 250 mm.

Amsterdam Precipitation Compared World Wide

Koh Samui’s average annual precipitation is 1645 mm. Let’s compare this to some popular worldwide tourist destinations:

New York City, USA, receives 1276 mm of rainfall annually, with precipitation evenly distributed throughout the year.

Beijing, China, receives 560 mm of annual precipitation, concentrated in the summer months.

In Tokyo, Japan, the average annual precipitation is 1528 mm, with significant summer rains due to typhoon season.

Singapore, situated near the equator, gets 2581 mm of rainfall annually, with no distinct dry season and consistent monthly precipitation.

How is Precipitation Measured?

Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.

Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.

Interesting weather facts

  • "Ginger" was the longest-lasting Atlantic tropical storm, which spun around the open ocean for 28 days in 1971.
  • The world's largest snowflake was recorded in the Guinness Book of Records, at 38 cm wide and 20 cm thick. The snowflake fell at Fort Keogh, Montana, USA, on 28 January 1887.
  • The greatest snowfall recorded was on Mt. Rainier, Washington State, USA—over 31.5 meters fell during the winter of 1972.

For more detailed information about Koh Samui’s weather, including sunshine hours, humidity levels, and temperature data, visit our Koh Samui Climate page.


Current rainfall in Koh Samui

Mon   Jan 06
29°C | 25°C
NE 5 m/s
2.7 mm
broken clouds and  chance of rain

broken clouds and chance of rain

Tue   Jan 07
29°C | 24°C
E 4 m/s
1.9 mm
partly cloudy and small chance of rain

partly cloudy and small chance of rain

Wed   Jan 08
30°C | 23°C
E 4 m/s
clear and no rain

clear and no rain

Interested in more climate information?

This site provides you with all the information you need about the climate in Koh Samui.

Our site offers climate and forecast data for every country in the world. Are you going to Thailand? On this website you can find historical weather averages for many cities in Thailand. Not sure yet where to go? We now have a tool which recommends destinations that suit your ideal travel conditions. Find out where to go with our weather planner.