People walk with umbrellas near Yonsei University in western Seoul, Monday. Yonhap

Monsoon season rains are forecast to drench the nation Wednesday, with rainfall expected to continue into the next day, the state-run weather agency said.

The broader Seoul area, inland parts of the eastern province of Gangwon and the central-western province of South Chungcheong already experienced rainfall overnight, with downpours forecast to hit the entire nation through Thursday, according to the Korea Meteorological Administration (KMA).

The KMA attributed the rainfall to a stationary front moving back and forth across Korea.

The broader Seoul area, inland and mountainous parts of Gangwon and central and northern parts of the southeastern province of North Gyeongsang are expected to see 50 to 100 millimeters of rainfall through Thursday, the KMA said.