South Korea will experience nationwide rain and strong winds on Wednesday, May 20, bringing a significant drop in temperatures [1].

This weather shift marks a sudden end to recent high-temperature trends, potentially disrupting travel and outdoor activities across the peninsula. The Korea Meteorological Administration said the change is due to the influence of a low-pressure system [1].

Forecasters expect heavy precipitation in several regions. The highest rainfall is projected for the Gangwon mountains, where totals could exceed 150 mm [1]. Jeju mountains are expected to see more than 120 mm [2], while the Seoul capital area, Yeongdong, and the southern coast may receive over 80 mm [2]. Some areas could experience hourly rainfall rates between 20 and 30 mm [2].

"Tomorrow, strong wind and rain will blow across the country, and the high-temperature phenomenon will subside," a Korea Meteorological Administration official said [1].

The cooling effect will be stark. Temperatures are expected to decrease by as much as 10 °C [2]. Predicted Wednesday morning temperatures include 19 °C in Seoul, 18 °C in Yeosu, and 17 °C in Daejeon [2].

Recent data shows the cooling trend has already begun. Reports on Tuesday varied slightly, with the temperature in Seoul recorded between 24.4 °C [2] and 25.1 °C [3]. One report said the temperature in Seoul was five degrees lower than the same time the previous day [2].

Residents in the capital region and mountainous areas are advised to prepare for the strong winds and heavy rainfall accompanying the low-pressure system [1].

“Tomorrow, strong wind and rain will blow across the country, and the high-temperature phenomenon will subside”

The rapid transition from high temperatures to heavy rain and a 10-degree drop indicates a volatile spring weather pattern. This sudden shift, driven by a low-pressure system, increases the risk of localized flooding in mountainous regions like Gangwon and Jeju, while the temperature plunge may catch residents unprepared for the sudden chill.