Sporadic showers will pelt the country throughout the week, turning into thunderstorms in central parts with a hailstorm forecast in the capital region.
The Korea Meteorological Administration said heavy squalls are expected across the country throughout this week under the influence of a low pressure trough moving towards the north of the Korean Peninsula.
Some 90 mm/h of rain poured down in Seoul's Gwanghwamun area on Sunday morning alone, with flash floods swelling to ankle height, and the pattern is likely to continue until the end of the week.
The KMA warned of hail in some parts of Gyeonggi and Gangwon provinces Monday due to unstable atmospheric conditions.
Hail has fallen in July only three times since 1973, all in Gangwon Province, but none in the Seoul metropolitan region for 119 years.
Hail is caused by abnormal friction between cold and warm air, often accompanied by heavy rains, thunderbolts and gusty winds.
