Heavy monsoon rains are expected to spread across South Korea starting Friday afternoon after a brief lull in the season [3].

The return of the heavy rain, known as jangmatbi, follows a period of high temperatures and atmospheric instability. This shift in weather patterns poses a risk of flash flooding and infrastructure disruption as the rain intensifies over the weekend.

Forecasters from the Korea Meteorological Administration, as referenced by YTN, said the rain will begin on Jeju Island before moving into the southern and central-southern regions [1, 2]. By Sunday, the heaviest downpours are projected to hit the Seoul metropolitan area and Gangwon Province [3].

Before the stationary front moves north, the country will experience heat and occasional showers through Friday afternoon [1]. National temperatures are expected to hover around 30 °C [1]. In certain areas, such as Gyeonggi Yeoju and Chungnam Gongju, the perceived temperature has already reached approximately 33 °C [1].

Kang Hye-mi, a forecast analysis officer at the Korea Meteorological Administration, said temperatures around 30 °C are expected nationwide until Friday afternoon, with showers occurring in some areas due to atmospheric instability [1].

The weather transition is driven by a stationary front that is currently moving northward. This system is expected to bring significant atmospheric instability, leading to the nationwide heavy rain forecast for the weekend [1, 2].

“Heavy monsoon rains are expected to spread across South Korea starting Friday afternoon.”

The rapid transition from high humidity and heat to intense monsoon rainfall often increases the risk of sudden flooding and landslides in South Korea's mountainous terrain. Because the rain is expected to peak on Sunday, local governments and residents in the Seoul metropolitan area and Gangwon Province must prepare for potential transport delays and emergency evacuations.