A heavy rain advisory was issued early Sunday morning for the inland area of Jeju, the southern island province, signaling the onset of this year's monsoon season, which is anticipated to be exceptionally wet.

According to the Korea Meteorological Administration, Jeju is expected to receive rain accumulating 100-200 millimeters through Monday, with some mountainous areas reaching up to 300 millimeters.

Downpours will then spread to upper parts of the country, with capital Seoul experiencing heavy rains from Monday.

The weather agency has forecast that the precipitation amount of this year’s monsoon season will likely exceed that of last summer.

President Yoon Suk Yeol, upon returning from Vietnam on Saturday evening, directed related government bodies to take preparations to minimize damage and to prevent any loss of life.

He specifically ordered thorough on-site inspections of flood-prone areas, in particular basement or semi-basement flats.

In summer of 2022, South Korea recorded heavy rain-related casualties amounting to a total of 25 deaths, of them several by drowning in basement parking lots or homes. Over 22,000 vehicles were submerged.