Heavy rain is forecast to fall across the country through Thursday, with more than 100 milliliters of precipitation expected for some regions.

According to the Korea Meteorological Administration, the rainy season is to begin in the central region on Tuesday, three or four days earlier than usual. The monsoon season is likely to continue until mid-July, it added.

The heavy rain is expected to spread across the entire nation on Tuesday, officials said.

The rain front, coming from North Korea, is expected to hit the central region, North Gyeongsang Province and the southern part of the country with up to 100 millimeters of rainfall on the day. The monsoon rain clouds will continue to move southward and hit the southern regions including Jejudo Island through Thursday, KMA said. Heavy rain with thunder and lightning will also hit areas of the southern region on Tuesday, it added.

“The rain front is expected to reach the Korean Peninsula starting tomorrow. With the North Pacific’s high atmospheric pressure expected drop, (the rain front) is likely to hit the rest of the country,” a KMA official said Monday.

“People should take extra care to ensure their safety as excessive rain could result in landslides, collapse of embankments and other natural disasters in some regions,” the official said.

The country will be soon gripped by a heat wave if the rain stops.

Temperatures in Seoul will drop to 23 degrees Celsius on Tuesday afternoon and will increase to 30 degrees Celsius on Thursday.

One or two typhoons are expected to hit the Korean Peninsula this summer.

By Cho Chung-un (christory@heraldcorp.com)