The state-run weather agency said monsoon season rains are forecast to drench the nation starting Wednesday, with rainfall expected to continue into Thursday.
The Korea Meteorological Administration attributed the rainfall to a stationary front moving back and forth across the country. The broader Seoul area, inland parts of Gangwon and central-western South Chungcheong already experienced rainfall overnight. Forecasts show 50 to 100 millimeters in Seoul, Gyeonggi and parts of Gangwon and North Gyeongsang through Thursday, while South and North Chungcheong and North Jeolla may receive 80 to 150 millimeters, with some spots exceeding 200 millimeters.
Interior Minister Yun Ho-jung instructed preparations against potential damage, dispatching officials to Gyeonggi Province, South Chungcheong Province and five other municipalities to check response measures. He called for precautionary safety steps such as verifying evacuation procedures and close coordination between central and local governments.
Daytime temperatures Wednesday are expected to range between 26 and 33 C. Rainfall is forecast to stop in many areas Thursday night, though the capital region and inland Gangwon may see continued downpours through Friday morning.