Torrential rain is forecast nationwide over the Children's Day holiday weekend.

According to the Korea Meteorological Administration, heavy showers are expected to start on Jeju Island from Wednesday afternoon and cross the country through Saturday morning.

Rain advisories may even be issued on Thursday in Jeju, the south coast, central regions and areas near Jiri Mountain.

Certain parts of Jeju will see between 200 to 400 millimeters of rain, while the wider capital region and western Gangwon Province will see over 120 millimeters.

The intensity of rainfall will be high, with over 50 millimeters expected per hour in the mountainous areas of Jeju and a maximum of 20 to 30 millimeters in metropolitan Seoul as well as the Gangwon, Chungcheong and Jeolla provinces.

"Torrential rain" typically refers to hourly precipitation above 30 millimeters or a daily total of over 80 millimeters. 

This week's rain will be accompanied by lighting, thunder and gusty winds.

Passengers using Jeju International Airport are advised to check the status of their flights beforehand against possible delays or cancellations.