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

    MonthAvg. High (°F)Avg. Mean (°F)Avg. Low (°F)
    Jan84.380.375.2
    Feb84.881.476.5
    Mar86.682.777.4
    Apr89.284.378.1
    May91.484.677.9
    Jun91.484.477.8
    Jul90.483.376.9
    Aug90.983.677
    Sep89.882.976.6
    Oct87.681.675.5
    Nov85.78174.9
    Dec85.280.775

    Show Celsius

    MonthAvg. High (°C)Avg. Mean (°C)Avg. Low (°C)
    Jan29.126.824
    Feb29.327.424.7
    Mar30.328.225.2
    Apr31.829.125.6
    May3329.225.5
    Jun3329.125.4
    Jul32.428.524.9
    Aug32.728.725
    Sep32.128.324.8
    Oct30.927.624.2
    Nov29.827.223.8
    Dec29.627.123.9


     

    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

    MonthDaily Chance of RainAverage Snow Depth (in)Total Precipitation (in)
    Jan25%04.9
    Feb10%01.4
    Mar16%07.1
    Apr21%03.6
    May32%06
    Jun26%04.7
    Jul32%05.1
    Aug22%03.1
    Sep26%03.6
    Oct49%011.2
    Nov53%020.1
    Dec32%010.1

    Show Centimeters

    MonthDaily Chance of RainAverage Snow Depth (cm)Total Precipitation (cm)
    Jan25012.4
    Feb1003.6
    Mar16018
    Apr2109.1
    May32015.2
    Jun26011.9
    Jul32013
    Aug2207.9
    Sep2609.1
    Oct49028.4
    Nov53051.1
    Dec32025.7

     

    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.

    MonthAvg. WindAvg. Wind FeelSustained High WindHigh Wind Feel
    Jan4.2Light breeze8.1Gentle breeze
    Feb4.9Light breeze8.1Gentle breeze
    Mar3.8Barely noticeable7.4Gentle breeze
    Apr2.2Barely noticeable6.2Light breeze
    May1.5Barely noticeable5.8Gentle breeze
    Jun1.7Barely noticeable5.9Light breeze
    Jul1.6Barely noticeable5.9Gentle breeze
    Aug2Barely noticeable6.4Light breeze
    Sep2Barely noticeable6.2Gentle breeze
    Oct1.9Barely noticeable6.3Light breeze
    Nov3Barely noticeable7.7Gentle breeze
    Dec3.7Barely noticeable7.8Gentle breeze

    Show Relative Humidity by Month

    MonthAvg. Relative Humidity
    Jan77.1%
    Feb75.9%
    Mar76.9%
    Apr76.8%
    May74.9%
    Jun71.7%
    Jul73.7%
    Aug71.9%
    Sep73.9%
    Oct79.5%
    Nov81.5%
    Dec78.2%

     

    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 Mar 17, 2019 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. This advisory was last updated on Mar 13, 2019.


     

    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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