CLIMATE OF NORTH AND SOUTH KOREA: SEASONS, RAINS, INFLUENCES

CLIMATE OF KOREA

The climate of Korea is temperate, with rainfall concentrated in summer and cold winters. North Korea has long, bitter winters. There are four seasons. Winter is long, cold, and dry. January is the coldest month, and average temperatures range from about 2°C (36°F) in southeastern Korea to about –21°C (–6°F) in parts of the northern mountainous region. Summer is short, hot, and humid, with late monsoon rains. In the hottest month, July, temperatures average between 21°C and 27°C (70°F and 81°F). [Source: CIA World Factbook]

In Seoul temperatures range from 22–29°C (71– 83°F) in the summers, and -7–1°C (19–33°F ) in the winter months, with warmer winter temperatures along the southern coast, and lower temperatures in the interior. Rainfall averages between 100 and 150 centimeters (40 and inches) annually, but many areas experience less rainfall. Rainfall is greatest in the south, and in inland mountainous regions. The coastal areas receive the least rainfall, on average. [Source: Geo-Data: The World Geographical Encyclopedia, The Gale Group Inc., 2003]

Annual rainfall varies from year to year but usually averages more than 100 centimeters (39 inches), two-thirds of precipitation falls between June and September. Annual rainfall varies from year to year and ranges from 50 centimeters (20 inches) in the northeastern inland region to 140 centimeters (55 inches) on the southern coast. Droughts, particularly in the southwest, occur approximately once every eight years. [Source: Library of Congress, May 2005; “Encyclopedia of World Cultures Volume 5: East / Southeast Asia:” edited by Paul Hockings, 1993]

Seasons in Korea

Korea has four distinct season, which are somewhat similar to those in the United States. The tempering effect of the ocean, which surrounds the Korean peninsula on three sides, keeps the temperatures lower than they otherwise would be. However the northern parts of the country around Seoul and the mountains can be quite cold in the winter. North Korea is even colder.

Spring and autumn are pleasant but short in duration. Springs is ushered in by plum blossoms in March and cherry blossoms in April, and is pleasant and sometimes rainy. Autumn begins in September and is characterized by falling leaves, crisp, cool, days and rice harvests. South Korea has pretty autumn colors.

Winter tends to be mild in the south and cold and long in the north. Northwest winds occasionally sweep across from the Asian continent bringing snow and freezing temperatures. Seoul often gets snow. The mountains in northern South Korea and in the interior can receive quite a lot of snow but are pleasantly cool in the summer. Annual rainfall varies a great deal from year to year and ranges from 50 centimeters (18 inches) in the northeastern inland region and 140 centimeters (55 inches) on the southern coast. About 70 percent of the annual precipitation false between June and September.

South Korea can be very muggy, hot and humid in the summer especially in August and September. The humid rainy season last for about a month, from mid-June to mid-July. On most days of rainy season it rains for one two hours or less. The temperatures are significantly cooler than later in the summer. The typhoon season lasts from late spring to early autumn. Most typhoons that strike Korea arrive in September and generally come ashore in southern South Korea and dissipate as they move north.

Rainy Season in Korea (Changma)

annual rainfall amounts in North and South Korea

Before the arrival of peak summer weather, the Korean Peninsula experiences a humid, damp rainy season known locally as Changma. This weather system typically moves from south to north across the peninsula, starting in late June and lasting through mid-July. The timing and intensity feature regional variations, but this period accounts for a massive portion of the region's annual precipitation. On average, Korea receives between 100 and 250 centimeters (39 to 98 inches) of rainfall annually, with the bulk of it concentrated during these critical weeks.

This seasonal phenomenon is driven by a massive meteorological collision. From May until July, a high-pressure mass of cold, maritime air hovers above the Sea of Okhotsk to the north, while a high-pressure mass of warm, moist air develops over the North Pacific Ocean. Where these two competing air masses collide, they form a stationary "rainy season front" that stretches from southern China across the Korean Peninsula and into Japan. This front stalls over the region, resulting in heavy, prolonged, and often torrential downpours rather than short showers. By late July, the dominant Pacific air mass finally pushes the front northward, bringing a definitive end to the rainy season.

According to NASA: Each year as the Earth’s orbit brings the Northern Hemisphere back under more direct sunlight, the Asian continent starts to heat up. Land surfaces have less heat capacity than surrounding oceans, and they heat up faster. This land-sea temperature difference causes the winds to shift; warm air rises over the continent, and moist air from over the oceans flows in to replace it. In East Asia, the boundary between the warm, humid air from the ocean to the south and the continental air to the north often becomes more or less stationary. This stationary front is known as the Baiu front in Japan and as the Mei-yu front in China. The location of the front migrates slowly northward over eastern China, Korea, Taiwan, and Japan over the course of spring and early summer, providing a focus for showers and rain, especially when waves of low pressure move along the front. Mei-yu means “plum rains” in Chinese, so called because the widespread rains often occur at the time when plums ripen, which is typically May and June. Baiu season in Japan typically runs from June through July. [Source: NASA Earth Observatory]

Once the Changma front clears, seasonal winds from the Pacific Ocean blanket Korea in intense heat and humidity. This transition triggers a punishing summer heatwave, locally called Mudaewi, where temperatures regularly soar above 30 degrees Celsius (86°F) and often surpass 35°C. Because the tropical night phenomenon keeps evenings sweltering, these post-rainy season weeks bring consecutive days of extreme heat with very little relief.

It is a good idea to bring along a fold up umbrella if you visit Korea at this time of year. . It rains a lot in South Korea and rain often starts unexpectedly. If you don't have an umbrella you can often buy a cheap one on the streets or in a convenience store or small shop.

Weather Patterns in Korea

Korea is part of the East Asian monsoonal region. The movement of air masses from the Asian continent exerts greater influence on South Korea's weather than does air movement from the Pacific Ocean.[Source: Andrea Matles Savada and William Shaw, Library of Congress, 1990 *]

South Korea generally has sufficient rainfall to sustain its agriculture. Rarely does less than 75 centimeters (30 inches) of rain fall in any given year; for the most part, rainfall is over 100 centimeters (39 inches). Things are different in North Korea which periodically suffers serious droughts.

Korea is less vulnerable to typhoons than Japan, Taiwan, the east coast of China, or the Philippines. From one to three typhoons can be expected per year. Typhoons usually pass over South Korea in late summer, especially in August, and bring torrential rains. Flooding occasionally causes considerable damage. In September 1984, record floods caused the deaths of 190 people and left 200,000 homeless. This disaster prompted the North Korean government to make an unprecedented offer of humanitarian aid in the form of rice, medicine, clothes, and building materials. South Korea accepted these items and distributed them to flood victims.

Yellow dust from north-central China blows into Korea and Japan during the spring. El Niño causes a wet summer and prolonged monsoons in Korea. During the La Niña, Korea is cooler,

Regional Climate Differences in Korea

(a) Average winter (left) and summer (right) temperatures in Korea Researchgate

Seoul's mean temperature in January is -5° C to — 2.5° C; in July the mean temperature is about 22.5° C to 25° C. Because of its southern and seagirt location, Cheju Island has warmer and milder weather than other parts of South Korea. Mean temperatures on Cheju range from 2.5° C in January to 25° C in July.

The average temperature in January ranges from -5°C (23°F) in Seoul to -2°C (28°F) in Busan and 4°C (39°F) on Jeju Island. However, in the hottest part of the summer, the regional variation in temperature is not nearly as significant, with average temperatures ranging from 77 to 81°F (25 to 27°C) in most lowland areas.

Average annual rainfall is 100 to 150 centimeters (40 to 50 inches). Nearly all of this rainfall occurs during the April–September period, especially during the rainy season from late June to early August. One to three mild typhoons typically hit the south in early fall, and a severe typhoon occurs every two to three years. There are about 240 days free of frost in the southern regions. [Source: Worldmark Encyclopedia of Nations, Thomson Gale, 2007]

Climate of North Korea

North Korea has four seasons, and the climate of the country is not all that different from Boston or Buffalo. Spring is pleasant, sunny and mild. Summer is characterized by a three-week-long rainy season followed by hot, humid weather. Autumn is crisp, cool, dry and highlighted by sunny days. The winter is cold, long and dry and influenced by cold fronts sweeping in from Manchuria. There is snow in the mountains and freezing temperatures.

North Korea is located between 38 and 43 north latitude and is just south of the Russian Far East, .The long bitterly cold winters are characterized by clear weather interspersed with snow storms that are a result of northern and northwestern winds that blow from Siberia. The daily average high and low temperatures for Pyongyang in January are -3° C and -13° C. Average snowfall is thirty-seven days during the winter. The weather is likely to be particularly harsh in the northern, mountainous regions. [Source: Andrea Matles Savada, Library of Congress, 1993 *]

Annual rainfall varies a great deal from year to year and ranges from 50 centimeters in the northeastern inland region and 140 centimeters on the southern coast. Approximately 60 percent of the annual rainfall, from 75 to 100 centimeters (30 to 40 inches), occurs from June through September.

The rainy season lasts from around mid-June to mid-July. Typhoons—which are much more likely to hit South Korea—may occur between July and September. North Korean typhoons are characterized more by heavy rain than super strong winds. The tempering effect of the ocean, which surround the Korean peninsula on three sides, keeps the helps moderate temperatures.

In the winter of 2001, a combination of extremely cold weather and lack of heat had fatal results. In Pyongyang the temperatures dropped to 8°C 30°C (-22°F). Frostbite became a common infliction and corpses were seen being carried out of apartment buildings.

Seasons and Regional Climate Variations in North Korea

North Korea has long, cold, dry winters and short, hot, humid summers. The temperatures range between –8E C in December and 27E C in August. August is the wettest month with an average rainfall of 32 centimeters. The northernmost regions receive less rainfall, averaging 50 centimeters (20 inches). [Source: Junior Worldmark Encyclopedia of Physical Geography, The Gale Group, Inc., 2003; Library of Congress, July 2007]

The temperature in North Korea varies from north to south during the winter, with the average January temperature at -17°C (1°F) along the northern border and -8°C (18°F) at P'yongyang, the capital. Summer temperatures have less variation from north to south, averaging 21°C (70°F) in the north, and 24°C (75°F) at P'yongyang.

Summer in North Korea tend to be short, hot, humid, and rainy because of the southern and southeastern monsoon winds that bring moist air from the Pacific Ocean. The daily average high and low temperatures for Pyongyang in August are 29° C and 20° C (84°F and 68°F). On average, approximately 60 percent of all precipitation occurs from June to September. Typhoons affect the peninsula on an average of at least once every summer. Spring and autumn are transitional seasons marked by mild temperatures and variable winds and bring the most pleasant weather. [Source: Andrea Matles Savada, Library of Congress, 1993]

Heavy Snows in Seoul

South Korea occasionally experiences severe snowstorms that disrupt transportation, close schools, damage buildings, and affect daily life. While Seoul generally receives less snow than colder inland or mountainous regions, major storms have periodically brought record accumulations to the capital and surrounding areas. Heavy snow often develops when cold continental air from Siberia meets moist air over the Yellow Sea, producing intense snowfall across western and central parts of the Korean Peninsula.[Source: Kim Tong-Hyung, Associated Press, January 26, 2023; Lee Jin-man, Associated Press, January 4, 2010; BBC, 14 February 2011]

In January 2023, a snowstorm swept across Seoul and neighboring regions during a period of unusually cold weather. More than 5 centimeters (2 inches) of snow fell in Seoul within 24 hours, while nearby Gyeonggi Province and Incheon received 6 to 8 centimeters (2.3 to 3.1 inches). Temperatures dropped to around -10°C (14°F), creating icy roads and hazardous walking conditions. Authorities deployed about 2,100 workers and 1,100 vehicles to spread more than 3,100 tons of salt and snow-removal chemicals on roads and expressways. Although major transportation networks remained largely operational, hundreds of homes reported frozen or burst water pipes, and some hiking trails in national parks were closed.

One of Seoul’s most significant snowstorms occurred on January 4, 2010, when more than 25 centimeters (10 inches) of snow fell on the city. The Korea Meteorological Administration described it as the heaviest snowfall in Seoul since modern records began in 1937. The storm paralyzed road traffic, packed subway trains with commuters avoiding icy roads, and caused major disruptions at airports. At Gimpo Airport, 224 flights were canceled, while Incheon International Airport reported dozens of cancellations and more than 100 delays. Thousands of workers and soldiers were mobilized to clear snow from roads, sidewalks, and public facilities.

Heavy snow has also affected other parts of South Korea more severely than Seoul itself. In February 2011, Gangwon Province on the east coast experienced some of the heaviest snowfall in more than a century. One city recorded about 80 centimeters (31 inches) of snow in a single day, the largest 24-hour snowfall since records began there in 1911. Hundreds of homes collapsed under the weight of accumulated snow, roads were blocked, schools were closed, and thousands of soldiers were deployed to assist stranded residents and clear transportation routes.

Another major snow event struck South Korea in March 2004, when central provinces received record March snowfall. The city of Daejeon recorded about 49 centimeters (19 inches) of snow in a single day, the highest one-day March total since meteorological records began in 1904. Roads across central South Korea became impassable, transportation was disrupted, and large areas were covered by deep snow visible from satellite imagery.

Heavy snowstorms in and around Seoul typically cause traffic congestion, flight cancellations, train delays, school closures, and occasional damage to buildings and infrastructure. Authorities regularly mobilize snow-clearing crews, military personnel, and emergency services to keep transportation networks functioning and assist affected residents. Despite modern snow-removal capabilities, major winter storms continue to pose significant challenges for South Korea’s densely populated capital region.

Heat Wave in South Korea in 2016

South Korea experienced an unusually intense heat wave during the summer of 2016, with Seoul recording its highest number of heat-wave days since 1994. Temperatures in the capital frequently exceeded 33°C (91°F), while nighttime temperatures often remained above 25°C (77°F), creating persistent tropical nights that offered little relief from the heat. The Korea Meteorological Administration issued heat-wave warnings for 11 consecutive days, reflecting the prolonged nature of the extreme weather. [Source: Kim Da-sol, Korea Herald, August 15, 2016; Hong Dam-young, Park Si-soo, Korea Times, August 4, 2016]

The heat was particularly severe in August. On August 14, Busan recorded a temperature of 37.3°C (99.1°F), the highest temperature measured there since records began in 1904. Many parts of the country, including Seoul and Gyeonggi Province, saw temperatures rise above 36°C (97°F). Weather officials attributed the conditions to a strong North Pacific high-pressure system combined with unusually hot air moving from northern China. The stable high-pressure system suppressed cloud formation, allowing intense sunshine to heat the Korean Peninsula for extended periods.

The prolonged heat wave caused a rise in heat-related illnesses and deaths. Authorities reported cases of heatstroke across the country, and several fatalities were linked to prolonged exposure to high temperatures. In one incident, a woman in her 90s died after working outdoors in a field during the extreme heat. Health officials also reported increasing numbers of heatstroke cases in several provinces, particularly among elderly residents and outdoor workers.

The heat affected daily life and strained infrastructure. Electricity demand reached record levels as households and businesses relied heavily on air conditioning and electric fans. South Korea's peak power consumption exceeded 85 million kilowatts, setting new national records and reducing reserve power supplies to levels that prompted government concern. To help consumers cope with higher electricity costs, the government introduced temporary reductions in household electricity bills during the summer months.

Retailers reported a surge in demand for cooling appliances. Sales of air conditioners reached their highest levels in several years, while fan sales increased sharply as consumers sought relief from the heat. Energy-efficient models were particularly popular because of concerns about electricity costs. Manufacturers struggled to keep pace with demand as stores reported shortages of some cooling products.

Meteorologists warned that the heat wave could continue through August and into September. The combination of hot, humid air and persistent high pressure produced one of South Korea's most notable heat events in recent decades. The summer highlighted the country's vulnerability to prolonged extreme heat and the growing challenges posed by increasingly frequent and intense heat waves.

Image Sources: Wikimedia Commons

Text Sources: South Korean government websites, Korea Tourism Organization, Cultural Heritage Administration, Republic of Korea, UNESCO, Wikipedia, Library of Congress, CIA World Factbook, World Bank, Lonely Planet guides, New York Times, Washington Post, Los Angeles Times, National Geographic, Smithsonian magazine, The New Yorker, “Culture and Customs of Korea” by Donald N. Clark, Chunghee Sarah Soh in “Countries and Their Cultures”, “Columbia Encyclopedia”, Korea Times, Korea Herald, The Hankyoreh, JoongAng Daily, Radio Free Asia, Bloomberg, Reuters, Associated Press, BBC, AFP, The Atlantic, The Guardian, Yomiuri Shimbun and various books and other publications.

Updated in June 2026