Seoul’s July Tropical Nights Most Severe in 117 Years

Highest Record in 117 Years... Tied with 21 Days in 1994
Heat Wave and Tropical Nights Continue Today... Expected to Last Until Next Week

Children enjoying water play at the fountain in Gwanghwamun Square, Jongno-gu, Seoul. Photo by Jo Yongjun

The tropical nights in Seoul this July have set a new record for the highest number since the Korea Meteorological Administration began observations 117 years ago. This matches the total of 21 days recorded in 1994, but when there is a tie, the most recent record is recognized as the highest.

According to the Korea Meteorological Administration on July 30, the lowest temperature in Seoul last night was 28.3 degrees Celsius, exceeding the tropical night threshold of 25 degrees. This marks the 11th consecutive day of tropical nights since July 19, and the 21st day this month.

Tropical nights are becoming prolonged not only in Seoul but also across various regions nationwide. In Seogwipo, Jeju, tropical nights have continued for 15 days, while Incheon, Cheongju, and Gangneung have each experienced 10 consecutive days. The frequent tropical nights are attributed to several independent factors: the persistent heat accumulation caused by the Tibetan High and the North Pacific High; the continuous inflow of hot and humid air from the south and southwest; the foehn effect, which is the warming of air as southern and eastern winds cross the Sobaek and Taebaek mountain ranges; and the urban heat island effect.

The heat wave continues on July 30, which is the traditional midpoint of summer according to the lunar calendar. Heat wave advisories have been issued nationwide, except for some areas such as Hallasan in Jeju. The highest daytime temperatures are expected to range from 32 to 38 degrees Celsius. In most regions, the maximum perceived temperature will reach around 35 degrees, and tropical nights are expected to persist through the night.

An official from the Korea Meteorological Administration advised, "The risk of heat-related illnesses is high, so please refrain from outdoor activities and going out as much as possible. If you must work outdoors, make sure to drink water frequently and avoid prolonged agricultural work or working alone."