September weather forecast
Seoul, South Korea

The Dongdaemun Gate in Seoul city, South Korea
The Dongdaemun Gate in Seoul city, South Korea

Weather in September

September, the first month of the autumn in Seoul, is still a warm month, with an average temperature varying between 25.8°C (78.4°F) and 17.2°C (63°F).

Temperature

In Seoul, the average high-temperature in September slightly decreases from 29.6°C (85.3°F) in August to a still moderately hot 25.8°C (78.4°F). In September, in Seoul, the average low-temperature is 17.2°C (63°F).

Humidity

In Seoul, the average relative humidity in September is 69.2%.

Rainfall

In Seoul, during 9.1 rainfall days, 169.3mm (6.67") of precipitation is typically accumulated. Throughout the year, there are 108.8 rainfall days, and 1450.6mm (57.11") of precipitation is accumulated.

Daylight

The average length of the day in September in Seoul is 12h and 26min.
On the first day of September, sunrise is at 06:02 and sunset at 19:02. On the last day of the month, sunrise is at 06:26 and sunset at 18:17 KST.

Sunshine

In Seoul, South Korea, the average sunshine in September is 5.9h.

UV index

In September, the average daily maximum UV index in Seoul, South Korea, is 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 7 in September transform into the following instructions:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in September in Seoul?

The average relative humidity in September in Seoul is 69.2%.

How many days does it rain in September in Seoul?

In Seoul, South Korea, during September, the rain falls for 9.1 days and regularly aggregates up to 169.3mm (6.67") of precipitation.

How many hours of daylight does Seoul have in September?

In Seoul, the average day length in September is 12h and 26min.

When is the sunrise / sunset in September in Seoul?

On the first day of September in Seoul, South Korea, sunrise is at 06:02 and sunset at 19:02. On the last day of the month, sunrise is at 06:26 and sunset at 18:17 KST.

How many hours of sunshine does Seoul have in September?

The average sunshine duration in September in Seoul is 5.9h.

What is the UV index intensity in September in Seoul?

In September, the average daily maximum UV index in Seoul, South Korea, is 7. A UV Index value of 6 to 7 symbolizes a high health threat from unprotected exposure to UV radiation.

Average temperature in September
Seoul, South Korea

Average temperature in September - Seoul, South Korea
  • Average high temperature in September: 25.8°C

The warmest month (with the highest average high temperature) is August (29.6°C).
The month with the lowest average high temperature is January (1.5°C).

  • Average low temperature in September: 17.2°C

The month with the highest average low temperature is August (22.4°C).
The coldest month (with the lowest average low temperature) is January (-5.9°C).

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Average humidity in September
Seoul, South Korea

Average humidity in September - Seoul, South Korea
  • Average humidity in September: 69.2%

The month with the highest relative humidity is July (78.3%).
The month with the lowest relative humidity is April (56.2%).

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Average rainfall in September
Seoul, South Korea

Average rainfall in September - Seoul, South Korea
  • Average rainfall in September: 169.3mm

The wettest month (with the highest rainfall) is July (394.7mm).
The driest month (with the least rainfall) is January (20.8mm).

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Average rainfall days in September
Seoul, South Korea

Average rainfall days in September - Seoul, South Korea
  • Average rainfall days in September: 9.1 days

The month with the highest number of rainy days is July (16.3 days).
The month with the least rainy days is February (5.8 days).

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Average daylight in September /
Average sunshine in September
Seoul, South Korea

Average daylight in September / Average sunshine in September - Seoul, South Korea
  • Average daylight in September: 12h and 26min

The month with the longest days is June (Average daylight: 14h and 43min).
The month with the shortest days is December (Average daylight: 9h and 37min).

  • Average sunshine in September: 5.9h

The month with the most sunshine is May (Average sunshine: 6.9h).
The month with the least sunshine is July (Average sunshine: 3.9h).

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Average UV index in September
Seoul, South Korea

Average UV index in September - Seoul, South Korea
  • Average UV index in September: 7

The month with the highest UV index is July (UV index 10).
The months with the lowest UV index are January and December (UV index 2).

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