South Korea experienced a heatwave with apparent temperatures reaching 33 °C to 35 °C before a monsoon-level rain system moved in nationwide [1], [2].
The rapid shift from extreme heat to heavy precipitation poses risks for infrastructure and public safety as the country enters its volatile rainy season.
High temperatures persisted on June 19, 2024, driven by a hot and humid air mass that had remained over the region for several days [1], [3]. In Seoul, as well as parts of Gyeonggi and inland Gyeongsangbuk-do, apparent temperatures reached 33 °C [1]. Other forecasts indicated that the apparent temperature in Seoul could climb as high as 35 °C [2].
Early morning readings at 8 a.m. showed temperatures of 26.0 °C in Seoul, 23.6 °C in Incheon, and 24.9 °C in Daejeon [1]. Other major cities recorded similar levels, with Gwangju at 24.7 °C, Daegu at 25.5 °C, Ulsan at 24.7 °C, and Busan at 24.4 °C [1].
The weather pattern shifted as a low-pressure trough moved north from the Shanghai region [1], [3]. This system, combined with an associated stationary front, triggered widespread rain described as being at a monsoon level [1].
Rain began on the night of June 19 and was expected to continue across the country through June 21 [1]. The precipitation affected multiple regions, including Seoul, Incheon, Daejeon, Gwangju, Daegu, Ulsan, and Busan, as well as the Gyeonggi, Gangwon, and Gyeongsangbuk-do provinces [1], [3].
Meteorologists said the transition was the result of the interacting air masses and the northward movement of the low-pressure system [1], [3].
“Apparent temperatures reached 33 °C to 35 °C before a monsoon-level rain system moved in nationwide.”
The convergence of a stagnant heatwave and a low-pressure system from China creates a high-energy atmospheric environment. This typically results in more intense precipitation and a higher risk of flash flooding, as the humid air mass provides significant moisture for the stationary front to process.
