ThailandThe weather in September in Ko Samui
It's hot in September in Ko Samui with an average temperature of 33°C. Temperatures this month range from a low of 32°C to a high of 33°C. At night, you can expect temperatures between 26°C and 27°C.
Looking for sun? September isn’t a good month to be in Ko Samui. The temperature is nice, but there’s too much chance of rain.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Ko Samui, Thailand. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.
Temperature records
With 35°C in 2017, Ko Samui reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 27°C in 2014. The extreme nighttime temperatures ranged from a lowest recorded value of 23°C to a highest value of 28°C.
Water temperature
The water temperature at Ko Samui is 31°C this month. It’s really warm, perfect for a swim.
Rainfall amount
In September, there is an average of 149 mm of precipitation, spread over 17 days. The wind speed is around 4 Bft, mostly coming from the West.
Daily weather in September for Ko Samui
Click on any day in September to get detailed info about the usual weather on that day in Ko Samui. Check out the historical temperatures and precipitation over the past 10 years on this day.
September weather comparison
| Ko Samui | New York | |
|---|---|---|
| Average temperature | 33°C | 27°C |
| Max. temperature | 33°C | 31°C |
| Min. temperature | 26°C | -5°C |
| Total precipitation | 149 mm | 57 mm |
| Rainy days | 17 days | 9 days |
Start of September
The month of September starts in Ko Samui with hot temps, averaging around 33°C during the day and nights around 27°C.
Mid September
By mid-September, daytime temps stay steady at around 33°C, with nights around 27°C. During this part of the month, you might see regular precipitation, but there will also be some sunny days.
End of September
By the end of September, the average daytime temperature in Ko Samui is around 33°C, while nighttime temps are about 27°C. Expect regular precipitation, but if you’re lucky, you’ll also get some dry and sunny days.
UV index
The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
The typhoon season in Ko Samui runs from June to November.
Check out the climate of Ko Samui for all months and discover the best travel time
Curious about the weather in other parts of Thailand? Check out the climate and weather for spots like Bangkok, Chiang Mai, Phuket, or explore other destinations in Thailand.
Temperature charts
These charts show the average temperatures in September in Ko Samui, Thailand. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in September in Ko Samui
Temperature in September in Ko Samui over the years
Precipitation charts
These charts show the average amount of precipitation in September in Ko Samui, Thailand. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.
Daily Precipitation in September in Ko Samui
Total precipitation in September in Ko Samui over the years
Daily UV index in September in Ko Samui
This chart shows the average daily UV index in September in Ko Samui, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Weather experiences in September in Ko Samui
Have you been to Ko Samui in September?
Share your weather experience in September in Ko Samui.
Average weather in Ko Samui by month
Click on a month below to see detailed weather info for Ko Samui. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.