September weather forecast
Seoul, South Korea

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

Weather in September

September ushers in the autumn spirit as it transitions from the sweltering summer. The city starts radiating hues of gold and brown, marking the beginning of fall. The comfortable autumn days in Seoul make it a popular month for touring the city's cultural landmarks. With this transition, the humidity drops to a comfortable 69.2%. October brings in the peak of autumn, with a significant drop in temperature.

Temperature

The arrival of September in Seoul signals a subtle shift in temperature, down from a moderately hot 29.6°C (85.3°F) in August to a still warm 25.8°C (78.4°F). Seoul sees an average low-temperature of 17.2°C (63°F) during September.

Humidity

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

Rainfall

In Seoul, in September, during 9.1 rainfall days, 169mm (6.65") of precipitation is typically accumulated. Throughout the year, in Seoul, there are 108.8 rainfall days, and 1451mm (57.13") of precipitation is accumulated.

Daylight

In Seoul, South Korea, the average length of the day in September is 12h and 26min.
On the first day of the month, sunrise is at 06:02 and sunset at 19:01. On the last day of September, sunrise is at 06:26 and sunset at 18:17 KST.

Sunshine

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

UV index

In Seoul, the average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV rays for average individuals.
Note: The daily high UV index of 7 during September translates into the following recommendations:
Eschew overexposure. Those with light skin may suffer burns in fewer than 20 minutes. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
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Frequently asked questions

What is the temperature in September in Seoul?

The average high-temperature, in September, in Seoul, is 25.8°C (78.4°F), while the average low-temperature is 17.2°C (63°F). In August, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines air temperature and relative humidity, is computed to be 35°C (95°F).

What is the average humidity in September in Seoul?

In Seoul, South Korea, the average relative humidity in September 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 169mm (6.65") of precipitation.

How many hours of daylight does Seoul have in September?

The average day length in September in Seoul, South Korea, is 12h and 26min.

What time are sunrise and sunset in September in Seoul?

On the first day of September in Seoul, sunrise is at 06:02 and sunset at 19:01. On the last day of the month, sunrise is at 06:26 and sunset at 18:17 KST.

How long on average sun shines in September in Seoul?

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

What is the UV index reading in September in Seoul?

In Seoul, South Korea, the average daily maximum UV index in September is 7. A UV Index estimate of 6 to 7 represents a high hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average UV index

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 2min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in September: 5h and 5min

The month with the most sunshine is May (Average sunshine: 6h and 54min).
The month with the least sunshine is July (Average sunshine: 3h and 54min).

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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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Seoul, South Korea

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