If you plan to visit Ko Samui in May, the weather is typically alright, with an average high temperature of +28°C during the day and approximately 0 sunny days. Expect some rainy, though, as there are typically 12 rainy days in the month and around 116 mm of precipitation. The weather is changeable so you may have to pack for every eventuality. Search flightsin one click on Avionero.
Average weather
☀️
+28°C
Avg. max. temperature
+21°C
Min.
+34°C
Max.
116 mm
Total precipitation
78%
Avg. humidity
2 m/s
Avg. wind
0 ☀️
Sunny Days
2 ⛅️
Cloudy
12 🌦
Rainy
Our opinion: Ko Samui has OK weather in May.
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Average temperature in Ko Samui in May
Here are the expected maximum, average and minimum temperatures in Ko Samui for May based on the historical data.
Last Year
Historical Data
Going from a maximum of +30°C during the day to a minimum of +25°C during the night, the temperature in May averages around +28°C.
The average maximum temperature goes up 20% by the end of the month, compared with the beginning of the month, from +26°C to +27°C.
Is Ko Samui warm or cold in May?
Ko Samui is typically warm in May.
Maximum temperatures go up compared to the previous month from +27°C to +28°C. The minimum temperature also goes up from +25°C to +25°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
May is one of the warmest months in Ko Samui, here is the comparison with other months:
Water temperature in Ko Samui in May
Water in Ko Samui in May is Very warm. It varies from +29°C to +31°C, with an average of +30°C.Note that the air temperature is lower than the water temperature, averaging around +28°C.
The water temperature in May is one of the warmest of the entire year:
The warmest water temperatures in Ko Samui are reached in May, when the average sea temperature rises to +30°C. The coldest water temperatures are in January, with an average of +28°C.
Can you swim in Ko Samui in May?
You can definitely swim in Ko Samui in May, the water is very warm (+30°C in average), and might even be unpleasant for ones who like it more fresh.
🦭
Cold
Below +16°C
🏄♂️
Fresh
16°C - 21°C
🏊
Comfortable
21°C - 25°C
👙
Warm
25°C - 28°C
🔥
Very warm
+28°C and up
Don't forget sunscreen and a hat, it's going to be hot!
Climate in Ko Samui in May
Ko Samui weather looks like this, on average, in May and the surrounding months.
April
May
June
Avg. temperature
+27°C
+28°C
+28°C
Min. temperature
+21°C
+21°C
+21°C
Max. temperature
+33°C
+34°C
+33°C
Rainfall
86 mm
116 mm
82 mm
Wind
2 m/s
2 m/s
3 m/s
Avg. water temperature
+30°C
+30°C
+30°C
Humidity
78%
78%
77%
Air pressure
1008 HPa
1008 HPa
1007 HPa
Sunny days
3
0
0
Cloudy days
6
2
4
Rainy days
12
12
15
Snowy days
0
0
0
May weather is still as ok as in April.It’s getting warmer as May arrives. The average maximum temperature goes up from +27°C to +28°C during the day.Prepare for more rain. Average rainfall goes from 86 mm to 116 mm.Humidity levels don’t change as the month goes on, averaging around 78%.The average wind speed doesn’t change much during May, staying around 2 m/s.The days becoming less sunny, going from 3 sunny days in April to 0 in May.
Wind speed in Ko Samui in May based on historical data.
Last Year
Historical Data
The average wind speed is 3 m/s getting up to 4 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Ko Samui is gradually increasing during May, going from 3 m/s to 4 m/s over the course of the month.
Rain
Amount of rainfall in mm during May in Ko Samui based on historical data.
Last Year
Historical Data
Typically, there is a 61% chance of rain on an average day in May, with total rainfall of approximately 64 mm. The maximum amount of rainfall per day is around 9 mm, which is considered light rain.May is a pretty wet month with over 19 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of galoshes.
Here’s how May is compared with other months in the amount of precipitation, total mm:
Ko Samui wettest month is November, where a typical day has a 57% chance of precipitation and 278 mm of rainfall per day. February, on the other hand, is the driest month with a mere 39% chance of precipitation and 29 mm of rainfall per day.
How was the weather last May in Ko Samui?
This is the weather in Ko Samui in May 2024:
1 May
🌧️
+26°C
2 May
🌧️
+26°C
3 May
☀️
+27°C
4 May
☀️
+27°C
5 May
☀️
+29°C
6 May
☀️
+29°C
7 May
☁️
+29°C
8 May
☀️
+29°C
9 May
☀️
+28°C
10 May
☁️
+27°C
11 May
☀️
+28°C
12 May
☀️
+29°C
13 May
☀️
+29°C
14 May
☀️
+29°C
15 May
☀️
+29°C
16 May
☀️
+28°C
17 May
☀️
+29°C
18 May
☀️
+29°C
19 May
☀️
+30°C
20 May
☀️
+29°C
21 May
☀️
+29°C
22 May
☀️
+28°C
23 May
☀️
+28°C
24 May
☀️
+29°C
25 May
☁️
+29°C
26 May
☀️
+29°C
27 May
🌧️
+29°C
28 May
☀️
+28°C
29 May
🌧️
+28°C
30 May
☁️
+27°C
31 May
🌧️
+27°C
In May 2024 Ko Samui had 22 sunny days, 4 cloudy days, and 5 rainy days. The average maximum temperature was +28°C, with an absolute maximum of +30°C and a minimum of +26°C. The average humidity was 80%, with a maximum of 100% and a minimum of 65%. The average wind speed was 3 m/s, with a maximum of 8 m/s and a minimum of 0 m/s.
Are you planning a trip in May?
Climate Change over Years
This is how Ko Samui climate have been changing during last 43 years period.
The climate in Ko Samui in May has not changed much over the last 43 years.
The average temperature was the lowest in 1986 (+26°C) and the highest in 2012 (+28°C). The driest year was 1997 with only 927 mm of rainfall, and the wettest year was 1999 with 1981 mm.
FAQ
Frequently asked questions about the weather in Ko Samui in May:
Is May a good time to visit Ko Samui?
It’s always a good time to visit Ko Samui, but the weather is changeable in May, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.
Can you sunbathe in Ko Samui in May?
May is warm in Ko Samui. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.
Can you swim in Ko Samui in May?
Yes, you can swim in Ko Samui in May, the water is very warm, with temperature averaging at +30°C, but it's important to manage hydration and sun exposure.
Is Ko Samui rainy in May?
Ko Samui is often rainy in May. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.
Is it sunny in Ko Samui in May?
Usually, it’s not very sunny in Ko Samui in May, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.
Other cities in Thailand
Check out the weather for other cities in Thailand.
For this page, we’ve looked at the typical weather in Ko Samui, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
