Seoul, June 26 : As heavy rain continued to lash South Korea on Monday, the greater Seoul area is expected to see up to 100 mm of downpour for two days, as the annual monsoon season has started, the state weather agency said.

The eastern coast of Gangwon Province will receive 10 to 50 mm throughout Monday, Yonhap News Agency quoted the KMA as saying.

Some regions will face torrential rains with 20 to 40 mm of rain per hour, accompanied by strong wind, lightning and thunder, until Tuesday, the weather agency said.

The KMA warned against using streamside trails and underground roadways, citing the danger of being stranded, and warned of flooding in lowlands and river torrents.

The temperature as of 10 a.m. Monday recorded 23.4 degrees Celsius in Seoul, 23.3 degrees in Daejeon, 24.5 degrees in Gwangju, 29 degrees in Jeju and 23.4 degrees in Busan, with daytime highs expected to range from 24 to 27 degrees.

Meanwhile, the Ministry of the Interior and Safety ordered public officials to take thorough preliminary steps for heavy rain. 

It also called for a speedy evacuation in case of flooding in semi-basement housing, underground parking lots and other vulnerable places.