Climate - Seoul (South Korea)

In Seoul, the capital of South Korea, located in the northwest of the country, a short distance from the coast of the Yellow Sea, the climate is continental, with cold, sunny winters and hot, sultry and rainy summers. Like the rest of Korea, the city is affected by the monsoon circulation: in winter, the northwest cold currents will prevail, while in summer, they will be replaced by hot and humid currents of tropical origin. Spring and autumn are transitional periods, mild and pleasant, especially the month of October.
Here are the average temperatures.

In winter, the average temperature is a few degrees below freezing (0 °C or 32 °F); sunshine is quite common, and a cold wind blows from the Asian continent. On colder periods, the temperature remains below freezing even during the day. The coldest record is -21.1 °C (-6 °F) and was set in January 1958.
Although the winter is a dry season, sometimes it can snow.
In winter, and especially in spring (March to May, which is called yellow dust season), the city can be affected by yellow dust (HwangSa in Korean), which comes from the desert of Mongolia and from China (though in truth, there is also a contribution given by local pollution) and forms a characteristic haze; it can also bring breathing problems and eye irritation.
Spring is mild, but the rains increase gradually. However, owing to the monsoon, the rainiest season is summer: from June to August, more than 800 millimeters (31.5 inches) of rain fall. The rains can sometimes be torrential. Usually, the worst month, the wettest and least sunny, is July. In summer, there can also be periods of good weather, which can be very hot, with highs about 35 °C (95 °F) and more. The highest record is 39.6 °C (103.3 °F) and was set in August 2018.
In autumn, rainfall decreases, and by October, the rains are quite rare. Here is the average precipitation.

From July to early October (and occasionally also in the second half of June), Seoul can be affected by typhoons, the tropical cyclones of South-East Asia, although this area of Korea is less exposed than the southern coast.



The amount of sunshine in Seoul is decent in winter, and also in spring and autumn (although it's lower than in the southern part of the country, like in Busan), while it hits a low in July because of the summer monsoon (the amount of sunshine drops to 27%, so cloudy skies prevail). Here are the average sunshine hours per day.

Near Seoul, the sea is very cold in winter, but it warms up a lot in summer, reaching 24 °C (75 °F) in August. Here are the average sea temperatures.

Seoul - Weather by month

Based on the period 1991-2020

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In January, the coldest month of the year, the weather in Seoul is usually very cold. The average temperature is of -2.1 °C (28 °F), with a minimum of -6.2 °C (20.9 °F) and a maximum of 2 °C (35.5 °F).
On the coldest nights of the month, the temperature usually drops to around -13 °C (8.5 °F). However, it dropped to -18.6 °C (-1.5 °F) in January 2001.
On the warmest days of the month, the temperature usually reaches around 9 °C (48.5 °F). However, it reached 13.5 °C (56.3 °F) in January 2002.
Precipitation amounts to 15 mm (0.6 in), distributed over 6 days.
The day lasts on average 9 hours and 55 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 55% of the time.
The average humidity is 55%.
The average wind speed is 8 kph (5 mph).

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In February, the weather in Seoul is usually cold. The average temperature is of 0.6 °C (33 °F), with a minimum of -3.8 °C (25.1 °F) and a maximum of 5 °C (41.1 °F).
On the coldest nights of the month, the temperature usually drops to around -11 °C (12.5 °F). However, it dropped to -17.1 °C (1.2 °F) in February 2012.
On the warmest days of the month, the temperature usually reaches around 13 °C (55.5 °F). However, it reached 17.9 °C (64.2 °F) in February 2010.
Precipitation amounts to 30 mm (1.2 in), distributed over 6 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 53%.
The average wind speed is 9 kph (6 mph).

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In March, the weather in Seoul is usually quite cold. The average temperature is of 6.1 °C (43 °F), with a minimum of 1.3 °C (34.4 °F) and a maximum of 10.9 °C (51.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -4.5 °C (23.5 °F). However, it dropped to -6.9 °C (19.6 °F) in March 2015.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 19 °C (66.5 °F). However, it reached 23.8 °C (74.8 °F) in March 2013.
Precipitation amounts to 35 mm (1.4 in), distributed over 7 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 53% of the time.
The average humidity is 53%.
The average wind speed is 10 kph (6 mph).

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In April, the weather in Seoul is usually mild. The average temperature is of 12.6 °C (55 °F), with a minimum of 7.4 °C (45.4 °F) and a maximum of 17.8 °C (64 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2 °C (35.5 °F). However, it dropped to -3.4 °C (25.9 °F) in April 1991.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25.5 °C (78 °F). However, it reached 29.8 °C (85.6 °F) in April 2005.
Precipitation amounts to 75 mm (3 in), distributed over 8 days.
The day lasts on average 13 hours and 10 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 53%.
The average wind speed is 10 kph (6 mph).

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In May, the weather in Seoul is usually warm. The average temperature is of 18.3 °C (65 °F), with a minimum of 13 °C (55.5 °F) and a maximum of 23.5 °C (74.3 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 9 °C (48 °F). However, it dropped to 5.8 °C (42.4 °F) in May 2010.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 30 °C (86.5 °F). However, it reached 33.3 °C (91.9 °F) in May 2014.
Precipitation amounts to 105 mm (4.1 in), distributed over 9 days.
The day lasts on average 14 hours and 10 minutes. So the days are long.
There are on average 7 hours of sunshine per day. So, the sun shines 51% of the time.
The average humidity is 58%.
The average wind speed is 9 kph (6 mph).

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In June, the weather in Seoul is usually warm to hot. The average temperature is of 22.9 °C (73 °F), with a minimum of 18.3 °C (65 °F) and a maximum of 27.5 °C (81.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 14.5 °C (58 °F). However, it dropped to 10.8 °C (51.4 °F) in June 1992.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 32.5 °C (90.5 °F). However, it reached 35.2 °C (95.4 °F) in June 2020.
Precipitation amounts to 130 mm (5.1 in), distributed over 10 days.
The day lasts on average 14 hours and 40 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 6.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 64%.
The average wind speed is 8 kph (5 mph).

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In July, the weather in Seoul is usually warm to hot and muggy. The average temperature is of 25.5 °C (78 °F), with a minimum of 22 °C (71.6 °F) and a maximum of 28.9 °C (84.1 °F).
On the coldest nights of the month, the temperature usually drops to around 19 °C (66 °F). However, it dropped to 16.2 °C (61.2 °F) in July 1993.
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F). However, it reached 38.4 °C (101.1 °F) in July 1994.
Precipitation amounts to 415 mm (16.3 in), distributed over 16 days.
The day lasts on average 14 hours and 25 minutes. So the days are long.
There are on average 4 hours of sunshine per day. So, the sun shines 28% of the time.
The average humidity is 75%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).

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In August, the warmest month of the year, the weather in Seoul is usually warm to hot and muggy. The average temperature is of 26.3 °C (79 °F), with a minimum of 22.6 °C (72.7 °F) and a maximum of 29.9 °C (85.9 °F).
On the coldest nights of the month, the temperature usually drops to around 18.5 °C (65 °F). However, it dropped to 14.6 °C (58.3 °F) in August 2005.
On the warmest days of the month, the temperature usually reaches around 34.5 °C (94.5 °F). However, it reached 39.6 °C (103.3 °F) in August 2018.
Precipitation amounts to 350 mm (13.8 in), distributed over 15 days.
The day lasts on average 13 hours and 30 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 73%. Hence, the air is normally humid.
The average wind speed is 8 kph (5 mph).

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In September, the weather in Seoul is usually warm. The average temperature is of 21.6 °C (71 °F), with a minimum of 17.2 °C (62.9 °F) and a maximum of 26.1 °C (79 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 12 °C (53.5 °F). However, it dropped to 8.4 °C (47.1 °F) in September 2010.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 31 °C (87.5 °F). However, it reached 32.8 °C (91 °F) in September 1998.
Precipitation amounts to 140 mm (5.5 in), distributed over 9 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 65%.
The average wind speed is 7 kph (4 mph).

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In October, the weather in Seoul is usually very mild. The average temperature is of 15.0 °C (59 °F), with a minimum of 9.9 °C (49.9 °F) and a maximum of 20.1 °C (68.2 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 3 °C (37 °F). However, it dropped to -2 °C (28.4 °F) in October 1997.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 26 °C (79 °F). However, it reached 29 °C (84.2 °F) in October 2014.
Precipitation amounts to 50 mm (2 in), distributed over 6 days.
The day lasts on average 11 hours and 10 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 60% of the time.
The average humidity is 60%.
The average wind speed is 7 kph (4 mph).

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In November, the weather in Seoul is usually quite mild. The average temperature is of 7.2 °C (45 °F), with a minimum of 2.7 °C (36.9 °F) and a maximum of 11.7 °C (53.1 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -5 °C (22.5 °F). However, it dropped to -10 °C (14 °F) in November 1996.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 19.5 °C (67.5 °F). However, it reached 25.9 °C (78.6 °F) in November 2011.
Precipitation amounts to 50 mm (2 in), distributed over 9 days.
The day lasts on average 10 hours and 5 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 59%.
The average wind speed is 8 kph (5 mph).

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In December, the weather in Seoul is usually very cold. The average temperature is of 0.0 °C (32 °F), with a minimum of -4.1 °C (24.5 °F) and a maximum of 4 °C (39.3 °F).
On the coldest nights of the month, the temperature usually drops to around -11 °C (11.5 °F). However, it dropped to -15.1 °C (4.8 °F) in December 2010.
On the warmest days of the month, the temperature usually reaches around 12 °C (53 °F). However, it reached 15.9 °C (60.6 °F) in December 2002.
Precipitation amounts to 25 mm (1 in), distributed over 8 days.
The day lasts on average 9 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 5.5 hours of sunshine per day. So, the sun shines 55% of the time.
The average humidity is 56%.
The average wind speed is 8 kph (5 mph).