Same Seoul but 'tropical night' days differ by 2 times… Changsin-dong 26 days, Jigwan-dong 12 days

During the same month, a significant difference emerged in the number of "열대야" (days with temperatures above 25°C) experienced across various Seoul neighborhoods. Despite the nationwide heatwave, the variation in 열대야 days within the city was notably pronounced, with some areas experiencing up to twice the number of such days compared to others.

Utilizing Seoul's "스마트서울 도시데이터 센서(S-DoT) 환경정보" and a generative artificial intelligence named "클로드," a report by the newspaper 한겨레 identified 창신동 as the neighborhood with the highest number of 열대야 days in July and August. On 26 days, temperatures in 창신동 reached or exceeded 25°C, according to the Seoul Meteorological Administration's criteria.

Following 창신동, cities with the most 열대야 days included 마장동 in 성동구, 25 days; 종로구's 종로1·2·3·4가동, 25 days; 역삼동 in 강남구, 24 days; 연남동 in 마포구, 24 days; and several other areas such as 숭인동, 종로5·6가동, 석촌동, 방이동, 영등포동, 대림동, 조원동, among others.

Conversely, the neighborhoods with the fewest 열대야 days were 은평구's 진관동, 도봉구's 도봉동, and 중랑구's 신내동, each experiencing only 12 such days. The official count of 열대야 days in Seoul for the same period was 14, yet the disparity between neighborhoods was as high as double. This variation was attributed to the urban heat island effect—a phenomenon where densely packed buildings and asphalt absorb and retain heat during the day, releasing it slowly at night, leading to higher temperatures in urban cores compared to surrounding areas.

Consequently, narrower streets and higher density housing in areas like 창신동 experienced more 열대야 days, while more spread-out areas like 삼청동 had fewer observations (15 days). Professor Hong Jin-gyu of Ewha Womans University noted that despite being part of the same city, 열대야 days could vary significantly based on factors such as building height, density, and the presence of green spaces.

He explained that older residential areas with many houses and higher building density could feel more heat due to insufficient insulation in buildings.