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Heat wave breaks May records as continued hot weather expected for start of June

Published: 31 May. 2026, 15:31

People cool off the water at a beach in Gangneung, Gangwon, on May 31. [YONHAP]

Ulleung County in North Gyeongsang recorded a record-high May morning low of 25.8 degrees Celsius (78.4 degrees Fahrenheit) on Sunday, as record-breaking morning heat was reported across the country, according to the Korea Meteorological Administration (KMA).

It marked the warmest morning recorded between 3 a.m. and 9 a.m. since weather observations began in the area in August 1938.

Similar records were set elsewhere along eastern coastal areas.

The city of Donghae in Gangwon posted a morning low of 23.5 degrees Celsius, also the highest ever recorded in May.

The northern part of Gangneung recorded a morning low of 21.8 degrees Celsius, while Gangneung, Uljin and Busan recorded lows of 25.0 degrees, 21.9 degrees and 20.6 degrees, respectively, with each marking their second-highest May reading on record.

Yeongdeok in North Gyeongsang recorded its third-highest May morning low on record at 21.2 degrees Celsius.

Records were broken outside the eastern coastal regions as well. Heuksan Island in South Jeolla recorded a morning low of 18.8 degrees — also an all-time high.

“The temperature was unable to fall overnight because warm southwesterly winds continued to flow into the country,” said Lee Yeong-ho, a KMA forecaster.

Satellite images shows temperature and humidity across Korea on May 31. [JOONGANG ILBO]

The agency’s weather analysis imagery shows a high-pressure system positioned over waters south of the Korean Peninsula. As a result, winds are circulating clockwise and continuously drawing in warm, humid southwesterly air.

The string of record-high morning temperatures along Korea's eastern shoreline was fueled by the foehn effect, which is when moist, moving air is forced to rise over a mountain range. This transformed moisture-laden southwesterly winds into hotter, drier air as they crossed the ridges of Mount Taebaek.

As a result, areas east of Mount Taebaek, known as the Yeongdong region, are experiencing particularly hot, dry weather.

Chuncheon in western Gangwon recorded a temperature of 26.3 degrees Celsius and humidity of 49 percent as of 11 a.m. on Sunday. In contrast, Gangneung along Gangwon's east coast was at 31.3 degrees Celsius, with humidity at just 26 percent.

The conditions also produced the year's first tropical night in Gangneung overnight between Saturday and Sunday.

The season's first tropical night arrived 19 days earlier than last year, when it occurred on June 18. A tropical night is defined when nighttime temperatures remain at or above 25 degrees Celsius from 6 p.m. through 9 a.m. the following day.

Daytime highs are expected to remain well above 30 degrees Celsius across much of the country through Wednesday.

Sunday’s high temperatures are forecast to range from 27 to 34 degrees Celsius. The heat is expected to persist next week, with daytime highs of 27 to 32 degrees on Monday, 24 to 33 degrees on Tuesday and 23 to 33 degrees on Wednesday.

Visitors flock to a beach in Sokcho, Gangwon, on May 30. [YONHAP]

Rain is forecast for the southern regions on Tuesday.

Expected precipitation totals range from 10 to 40 millimeters (0.39 to 1.6 inches) along coastal areas in South Jeolla, 20 to 60 millimeters in Busan, Ulsan and the South Gyeongsang areas and 30 to 80 millimeters on Jeju Island, with some areas receiving more than 120 millimeters.

Beginning Thursday, the heat is expected to retreat, with daytime highs falling below 30 degrees Celsius across most of the country, except for Daegu and Andong, which are inland cities in the North Gyeongsang region.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY HEO JEONG-WON [[email protected]]