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Ko Samui in July: Weather, Average temperature and Climate

Take a look at past year’s weather for Ko Samui in July and see if it is worth visiting.
Check flight prices to Ko Samui on Avionero:
July

Weather in Ko Samui in July 2025

OK Weather
Warm
🌧️
Rainy
🌊
Very warm water
Ko Samui in July usually sees fair weather conditions, with an average daily high temperature of +81°F and roughly 0 sunny days. However, you should prepare for about 17 rainy days with an average precipitation of 82 mm. The weather is changeable so pack for every eventuality. Search flights in one click on Avionero.

Average weather

☀️
+81°F
Avg. max. temperature
+70°F
Min.
+91°F
Max.
82 mm
Total precipitation
77%
Avg. humidity
3 m/s
Avg. wind
0 ☀️
Sunny Days
3 ⛅️
Cloudy
17 🌦
Rainy
Our opinion: Ko Samui has OK weather in July.

Average temperature in Ko Samui in July

Here are the expected maximum, average and minimum temperatures in Ko Samui for July based on the historical data.
Last Year
Historical Data

The temperature in July 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 up 0% by the end of the month, compared with the beginning of the month, from +81°F to +81°F.

Is Ko Samui warm or cold in July?

Ko Samui is typically warm in July.

Maximum temperatures go down compared to the previous month from +82°F to +81°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.

Take a look at how July is compared to other months in Ko Samui:

Water temperature in Ko Samui in July

Water in Ko Samui in July is Very warm. It varies from +84°F to +87°F, with an average of +86°F. Note that the air temperature is lower than the water temperature, averaging around +81°F.

The water temperature in July 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 +86°F. The coldest water temperatures are in January, with an average of +82°F.

Can you swim in Ko Samui in July?

You can definitely swim in Ko Samui in July, the water is very warm (+86°F in average), and might even be unpleasant for ones who like it more fresh.
🦭
Cold
Below +61°F
🏄‍♂️
Fresh
61°F - 70°F
🏊
Comfortable
70°F - 77°F
👙
Warm
77°F - 82°F
🔥
Very warm
+82°C and up
Don't forget sunscreen and a hat, it's going to be hot!

Climate in Ko Samui in July

Ko Samui weather looks like this, on average, in July and the surrounding months.
JuneJulyAugust
Avg. temperature
+82°F+81°F+81°F
Min. temperature
+70°F+70°F+68°F
Max. temperature
+91°F+91°F+91°F
Rainfall
82 mm82 mm85 mm
Wind
3 m/s3 m/s3 m/s
Avg. water temperature
+86°F+86°F+84°F
Humidity
77%77%78%
Air pressure
1007 HPa1008 HPa1008 HPa
Sunny days
000
Cloudy days
434
Rainy days
151718
Snowy days
000

July weather is still as ok as in June. It’s getting colder in July. From +82°F in the day, the average maximum temperature lowers to +81°F. The rainfall amount in July stays the same as in the previous month with a 82 mm of total precipitation. Humidity levels don’t change as the month goes on, averaging around 77%. The average wind speed doesn’t change much during July, staying around 3 m/s. The amount of sunny days stay about the same, averaging 0 sunny days during the month.

August brings much the same weather, it remains ok.

Wind

Wind speed in Ko Samui in July based on historical data.
Last Year
Historical Data

The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.

The average wind speed in Ko Samui is gradually decreasing during July, going from 4 m/s to 3 m/s over the course of the month.

Rain

Amount of rainfall in mm during July in Ko Samui based on historical data.
Last Year
Historical Data
A chance of rain on a typical day in July stands at 58%, leading to total precipitation of around 134 mm. The maximum amount of rainfall per day is around 27 mm, which is moderate rain. July is a pretty wet month with over 18 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of wellies.
Here’s how July 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 38% chance of precipitation and 29 mm of rainfall per day.

How was the weather last July in Ko Samui?

This is the weather in Ko Samui in July 2023:
1 July
🌧️
+81°F
2 July
☀️
+82°F
3 July
☀️
+81°F
4 July
☀️
+82°F
5 July
☀️
+83°F
6 July
☁️
+83°F
7 July
☁️
+83°F
8 July
🌧️
+81°F
9 July
☀️
+79°F
10 July
☀️
+81°F
11 July
☁️
+81°F
12 July
☀️
+83°F
13 July
☀️
+84°F
14 July
☀️
+83°F
15 July
☀️
+83°F
16 July
🌧️
+82°F
17 July
🌧️
+79°F
18 July
🌧️
+78°F
19 July
🌧️
+80°F
20 July
☀️
+82°F
21 July
🌧️
+79°F
22 July
🌧️
+79°F
23 July
🌧️
+79°F
24 July
☁️
+81°F
25 July
🌧️
+79°F
26 July
☀️
+80°F
27 July
☀️
+81°F
28 July
☀️
+81°F
29 July
☀️
+82°F
30 July
☀️
+83°F
31 July
☀️
+81°F
In July 2023 Ko Samui had 17 sunny days, 4 cloudy days, and 10 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 80%, with a maximum of 100% and a minimum of 68%. The average wind speed was 3 m/s, with a maximum of 11 m/s and a minimum of 0 m/s.
Are you planning a trip in July?

Climate Change Over the Years

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

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

The average temperature was the lowest in 1986 (+79°F) and the highest in 2012 (+83°F). 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 July:

Is July a good time to visit Ko Samui?

It’s always a good time to visit Ko Samui, but the weather is changeable in July, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.

Can you sunbathe in Ko Samui in July?

July 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 July?

Yes, you can swim in Ko Samui in July, the water is very warm, with temperature averaging at +86°F, but it's important to manage hydration and sun exposure.

Is Ko Samui rainy in July?

Ko Samui is often rainy in July. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.

Is it sunny in Ko Samui in July?

Usually, it’s not very sunny in Ko Samui in July, 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, 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.