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Seoul marks first tropical night of the year, daytime highs to reach mid-30s this week

Published: 30 Jun. 2025, 12:54

As cooling fog sprays from a mist system along a walking path in Jung District, Daegu, on June 30, people use handheld fans and personal fans to keep cool. [YONHAP]

Seoul recorded its first tropical night of the year on Sunday as a prolonged heat wave pushed temperatures well above average, with daytime highs expected to reach up to 36 degrees Celsius (96.8 degrees Fahrenheit) in some areas this week.

A steady inflow of hot, humid southwesterly winds kept nighttime temperatures from falling in parts of the country, including Seoul, according to the Korea Meteorological Administration (KMA) on Monday. The city’s overnight low, measured between 6:01 p.m. Sunday and 7 a.m. Monday, was 25.6 degrees Celsius.

A tropical night is defined when temperatures stay above 25 degrees Celsius between 6:01 p.m. and 9 a.m. the following day. With the mercury remaining above that threshold until 9 a.m. Monday, the KMA confirmed that Sunday marked Seoul’s first tropical night of 2025.

Last year, Seoul recorded its earliest-ever tropical night on June 21 since weather observations began in 1907. This year’s occurrence is eight days later than in 2024, though the city has now experienced tropical nights in June for four consecutive years since 2022, earlier than the usual start in July.

Other parts of the country also saw tropical nights, including Gangneung in Gangwon with 27 degrees Celsius, Cheongju in North Chungcheong with 25.3 degrees Celsius, Daegu with 25.8 degrees Celsius and Seogwipo in Jeju with 25.9 degrees Celsius. The warmest night was in Pohang, North Gyeongsang, where the temperature didn't drop below 27.4 degrees Celsius.

Beachgoers crowd Gyeongpo Beach in Gangneung, Gangwon, on June 29 to beat the heat. [YONHAP]

The KMA forecast that temperatures would rise sharply nationwide starting Monday afternoon, with heat wave advisories or warnings already in effect across much of the Chungcheong region and southern Korea. The rest of the country, including the Seoul metropolitan area, is also expected to be placed under heat wave alerts.

Gyeongju and Gimcheon in North Gyeongsang could see daytime highs soar to 36 degrees Celsius, while Seoul is expected to reach 30 degrees Celsius, with an apparent temperature of 32 degrees Celsius. Apparent temperature refers to the temperature felt by the human body at normal humidity.

Although passing rain or showers may briefly lower temperatures, humidity will remain high, and temperatures are likely to rebound once the rain stops, making conditions feel even hotter.

Children cool off in a water fountain in Damyang, South Jeolla, on the afternoon of June 29. [NEWS1]

With monsoon rains temporarily subsiding, the current spell of heat and tropical nights is expected to persist throughout the week.

“Most regions will experience extremely hot conditions, with maximum perceived temperatures around 33 degrees Celsius, and some areas will see more tropical nights,” a KMA official said.