The best times to visit Koh Samui for ideal weather are

January 29th to March 25th

based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.

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Weather in Koh Samui

Temperature

Average temperatures in Koh Samui vary very little. Considering humidity, temperatures feel hot all year with a chance of rain throughout most of the year. The area is far less temperate than some — in the 4th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Koh Samui, the hottest months are May, June, and then April. See average monthly temperatures below. The warmest time of year is generally mid April where highs are regularly around 92.2°F (33.4°C) with temperatures rarely dropping below 78.2°F (25.7°C) at night.

Koh Samui Temperatures (Fahrenheit)

Key
High
Average
Low

Koh Samui Temperatures (Celsius)

Key
High
Average
Low

“Feels-Like” Temperatures

The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.

Koh Samui Perceived Temperature (F)

Key
High
Average
Low

Koh Samui Perceived Temperature (C)

Key
High
Average
Low

 

Average Koh Samui Temperatures by Month

Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.

Show Fahrenheit

Month Avg. High (°F) Avg. Mean (°F) Avg. Low (°F)
Jan 84.3 80.3 75.2
Feb 84.8 81.4 76.5
Mar 86.6 82.7 77.4
Apr 89.2 84.3 78.1
May 91.4 84.6 77.9
Jun 91.4 84.4 77.8
Jul 90.4 83.3 76.9
Aug 90.9 83.6 77
Sep 89.8 82.9 76.6
Oct 87.6 81.6 75.5
Nov 85.7 81 74.9
Dec 85.2 80.7 75

Show Celsius

Month Avg. High (°C) Avg. Mean (°C) Avg. Low (°C)
Jan 29.1 26.8 24
Feb 29.3 27.4 24.7
Mar 30.3 28.2 25.2
Apr 31.8 29.1 25.6
May 33 29.2 25.5
Jun 33 29.1 25.4
Jul 32.4 28.5 24.9
Aug 32.7 28.7 25
Sep 32.1 28.3 24.8
Oct 30.9 27.6 24.2
Nov 29.8 27.2 23.8
Dec 29.6 27.1 23.9


 

Precipitation (Rain or Snow)

If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Koh Samui are February, March, and then April. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around early February. For example, on the week of February 5th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in late October with an average of 4 days of significant precipitation the week of October 22nd.

When can you find snow in Koh Samui? Weather stations report no annual snow. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.

Chanceof Precipitation

The graph below shows the % chance of rainy and snowy days in Koh Samui.

Key
Days with precipitation

Snow on the Ground

The graph below shows the average snow on the ground in Koh Samui (in).

Key
Snow depth

Average Rain and Snow by Month

Show Inches

Month Daily Chance of Rain Average Snow Depth (in) Total Precipitation (in)
Jan 25% 0 4.9
Feb 10% 0 1.4
Mar 16% 0 7.1
Apr 21% 0 3.6
May 32% 0 6
Jun 26% 0 4.7
Jul 32% 0 5.1
Aug 22% 0 3.1
Sep 26% 0 3.6
Oct 49% 0 11.2
Nov 53% 0 20.1
Dec 32% 0 10.1

Show Centimeters

Month Daily Chance of Rain Average Snow Depth (cm) Total Precipitation (cm)
Jan 25 0 12.4
Feb 10 0 3.6
Mar 16 0 18
Apr 21 0 9.1
May 32 0 15.2
Jun 26 0 11.9
Jul 32 0 13
Aug 22 0 7.9
Sep 26 0 9.1
Oct 49 0 28.4
Nov 53 0 51.1
Dec 32 0 25.7

 

Humidity and Wind

Koh Samui has some extremely humid months, and high humidity throughout the year. The least humid month is June (71.7% relative humidity), and the most humid month is November (81.5%).

Wind in Koh Samui is usually extremely calm. The windiest month is February, followed by January and March. February’s average wind speed of around 4.9 knots (5.6 MPH or 9 KPH) is considered “a light breeze.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in late January and early February where average top sustained speeds reach 9.4 knots, which is considered a gentle breeze.

Relative Humidity (%)

The graph below shows the average % humidity by month in Koh Samui.

Key
Avg. Relative Humidity

Wind

The graph below shows wind speed (max and average) in knots.

Key
Max Sustained Wind
Average Daily Wind

Average Wind Speeds

Show Wind Speeds

All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.

Month Avg. Wind Avg. Wind Feel Sustained High Wind High Wind Feel
Jan 4.2 Light breeze 8.1 Gentle breeze
Feb 4.9 Light breeze 8.1 Gentle breeze
Mar 3.8 Barely noticeable 7.4 Gentle breeze
Apr 2.2 Barely noticeable 6.2 Light breeze
May 1.5 Barely noticeable 5.8 Gentle breeze
Jun 1.7 Barely noticeable 5.9 Light breeze
Jul 1.6 Barely noticeable 5.9 Gentle breeze
Aug 2 Barely noticeable 6.4 Light breeze
Sep 2 Barely noticeable 6.2 Gentle breeze
Oct 1.9 Barely noticeable 6.3 Light breeze
Nov 3 Barely noticeable 7.7 Gentle breeze
Dec 3.7 Barely noticeable 7.8 Gentle breeze

Show Relative Humidity by Month

Month Avg. Relative Humidity
Jan 77.1%
Feb 75.9%
Mar 76.9%
Apr 76.8%
May 74.9%
Jun 71.7%
Jul 73.7%
Aug 71.9%
Sep 73.9%
Oct 79.5%
Nov 81.5%
Dec 78.2%

 

Is it Safe to Travel to Koh Samui?

Our best data indicates this area is somewhat safe, but with extra warnings in a few regions. As of Jan 18, 2018 there are travel warnings and regional advisories for Thailand; exercise a high degree of caution and avoid some areas. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories


 

The Busiest and Least Crowded Months

The busiest month for tourism in Koh Samui, Thailand is January, followed by August and July. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Koh Samui in May. Those willing to visit at these times will likely find it the least expensive month.

Estimated Tourism by Month

 

Most Popular Months to Visit

Key
Tourists Seeking Accommodations

Tourism graph is based on Google searches for services used by tourists relative to the rest of the year. Tourism data for this area is extrapolated based on nearby areas. Displayed data is calculated relative to the peak, so a score of 72.3 in May means 72.3% of the tourists vs. January.



Overall Koh Samui Travel Experience by Season

Spring (March through May)

Humidity and temperatures combine to make this season feel warm. Highs range from 92.2°F (33.4°C) and 85.8°F (29.9°C) with similar temperatures in the later months. Rain is somewhat common with 5 to 10 days of significant precipitation per month. Spring is the slowest for tourism, which makes it a good time for those looking for deals.

Summer (June through August)

The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see moderate precipitation with 7 to 10 days of precipitation per month. June – August is the second busiest season for tourism in Koh Samui, so lodging and other accommodations may cost slightly more.

Fall (September through November)

Fall daily highs range from 89.9°F (32.2°C) and 85.2°F (29.6°C), which will feel very nice given the humidity and wind. It rains or snows a great amount: 8 to 16 days per month. Tourism is fairly slow during these months due to the weather, so hotels may be lower priced.

Winter (December through February)

Weather is perfect this time of year in Koh Samui to be enjoyable for warm weather travelers. The average high during this season is between 85.8°F (29.9°C) and 83.9°F (28.8°C). On average, it rains or snows a fair amount: 3 to 10 times per month. These times of year are the busiest with tourists.

 

Best Times to TravelThailand › Koh Samui, Thailand

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