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Ko Samui in May: Weather, Average temperature and Climate

Planning a trip and want to know what the weather in Ko Samui in May will be like? Take a look at our weather guide for Ko Samui, based on historical data.
Check flight prices to Ko Samui on Avionero:
May

Weather in Ko Samui in May 2024

OK Weather
Warm
☁️
Cloudy
Ko Samui in May usually sees fair weather conditions, with an average daily high temperature of +82°F and roughly 1 sunny days. However, you should prepare for about 14 rainy days with an average precipitation of 117 mm. The weather is changeable so pack for every eventuality. Search flights in one click on Avionero.

Average weather

☀️
+82°F
Avg. max. temperature
+70°F
Min.
+93°F
Max.
117 mm
Total precipitation
78%
Avg. humidity
2 m/s
Avg. wind
1 ☀️
Sunny Days
16 ⛅️
Cloudy
14 🌦
Rainy
Our opinion: Ko Samui has OK weather in May.

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

The temperature in May is +81°F on average, with a range between a maximum of +84°F during the day and a minimum of +75°F at night.

The average maximum temperature goes down 20% by the end of the month, compared with the beginning of the month, from +82°F to +81°F.

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 +81°F to +82°F. The minimum temperature also goes up from +77°F to +77°F.

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:

Climate in Ko Samui in May

Ko Samui weather looks like this, on average, in May and the surrounding months.
AprilMayJune
Avg. temperature
+81°F+82°F+82°F
Min. temperature
+70°F+70°F+70°F
Max. temperature
+91°F+93°F+91°F
Rainfall
88 mm117 mm83 mm
Wind
2 m/s2 m/s2 m/s
Humidity
78%78%77%
Air pressure
1008 HPa1007 HPa1007 HPa
Sunny days
510
Cloudy days
171619
Rainy days
81411
Snowy days
000

May weather is still as ok as in April. It’s getting warmer as May arrives. The average maximum temperature goes up from +81°F to +82°F during the day. Prepare for more rain. Average rainfall goes from 88 mm to 117 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 5 sunny days in April to 1 in May.

June brings much the same weather, it remains ok.

Wind

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 5 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 1 m/s to 3 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 77% chance of rain on an average day in May, with total rainfall of approximately 237 mm. The maximum amount of rainfall per day is around 29 mm, which is moderate rain. May is a pretty wet month with over 24 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of wellies.
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 276 mm of rainfall per day. February, on the other hand, is the driest month with a mere 7% chance of precipitation and 30 mm of rainfall per day.

How was the weather last May in Ko Samui?

This is the weather in Ko Samui in May 2023:
1 May
☀️
+83°F
2 May
🌧️
+81°F
3 May
🌧️
+79°F
4 May
🌧️
+80°F
5 May
🌧️
+80°F
6 May
🌧️
+79°F
7 May
🌧️
+79°F
8 May
🌧️
+80°F
9 May
🌧️
+81°F
10 May
🌧️
+80°F
11 May
🌧️
+80°F
12 May
☀️
+81°F
13 May
☀️
+82°F
14 May
☀️
+82°F
15 May
🌧️
+83°F
16 May
☀️
+82°F
17 May
☀️
+82°F
18 May
🌧️
+81°F
19 May
☀️
+82°F
20 May
☀️
+82°F
21 May
☁️
+82°F
22 May
☀️
+83°F
23 May
☀️
+84°F
24 May
☀️
+83°F
25 May
☁️
+83°F
26 May
☀️
+84°F
27 May
☀️
+84°F
28 May
🌧️
+80°F
29 May
🌧️
+79°F
30 May
☁️
+79°F
31 May
☀️
+81°F
In May 2023 Ko Samui had 14 sunny days, 3 cloudy days, and 14 rainy days. The average maximum temperature was +81°F, with an absolute maximum of +84°F and a minimum of +79°F. The average humidity was 78%, with a maximum of 100% and a minimum of 55%. The average wind speed was 3 m/s, with a maximum of 9 m/s and a minimum of 0 m/s.
Are you planning a trip in May?

Climate Change Over the Years

This is how Ko Samui climate has changed over the last 43 years.

The climate in Ko Samui in May has not changed that much over the last 43 years.

The average temperature was the lowest in 1999 (+85°F) and the highest in 2019 (+89°F). The driest year was 1997 with only 42 mm of rainfall, and the wettest year was 2022 with 253 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.

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.

Monthly weather in Ko Samui

Source of the data

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, 2022.

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.