Pedestrians walk in rain at Gwanghwamun Square in Jongno, central Seoul, June 13. (Yonhap) South Korea is expecting rain in the southern region that will spread across the country later Friday, with showers anticipated for much of the weekend, according to the weather authorities.The Korea Meteorological Administration forecast cloudy day across the country, with rainfall that starts at Jeju Island expanding to the North and South Jeolla provinces. By nightfall, most of the country is expecting rain.Around 50 to 150 milliliters of accumulated precipitation is expected for Friday and Saturday in Jeju Island, with over 250 milliliters of rain expected for some mountain regions. The east coast region is expecting somewhere between 50 and 100 milliliters, while 50-100 milliliters is forecast for Gwangju and South Jeolla Province, along with 30-80 milliliters expected for North Jeolla Province.The southeastern region of North and South Gyeongsang provinces and Busan is expecting between 30 and 80 milliliters of rain, with possibly over 100 milliliters in some southern coastal regions and Jirisan.Inland regions will have relatively less precipitation, such as 10-40 milliliters for Seoul, Incheon and Gyeonggi Province and 10-60 milliliters for inland parts of Gangwon Province. The North and South Chungcheong provinces, Daejeon and Sejong are expecting 20-60 milliliters in the two-day span.The KMA forecast possible torrential rain between Friday night and the wee hours of Saturday of between 30 and 50 milliliters per hour. Jeju Island and the southern coast in particular can expect heavy rainfall entailing wind and lightning, the agency noted.The KMA said rainfall over the weekend does not herald the beginning of the country's monsoon season, which typically begins around June 19 on Jeju Island and four to six days later on the mainland. While monsoon season in Korea takes place with a persistent inflow of warm, humid air from the south, the latest humid air showering the peninsula is expected to head back southward on Sunday.This year's monsoon season will likely begin later than the average of the past 30 years.While rain will cease for most regions, the east coast of Gangwon Province is expecting rain until Sunday afternoon.