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Extreme rainfall to hit on Sunday, lowering temps but risking flood damage

Published: 03 Aug. 2025, 13:14

Citizens battle through the pouring rain in Jeonju, North Jeolla, on July 17. [NEWS1]

After a spell of extreme heat, torrential rains at an extreme level are forecast to lash the country starting Sunday afternoon. Parts of the southern regions are expected to receive more than 250 millimeters (9.8 inches) of rainfall through Tuesday morning, raising concerns of further damage from floods.

“Today and tomorrow, strong and heavy rain accompanied by gusts, lightning and thunder is expected across most of the country,” the Korea Meteorological Administration (KMA) said in its forecast Sunday.

As of 10 a.m. Sunday, rain was falling in the Jeolla regions and on Jeju Island. It was expected to spread to the rest of the country, including the capital area, by the afternoon.

The downpour is forecast to intensify in the afternoon, with a strong rain band moving in from the Yellow Sea and bringing concentrated rainfall of 30 to 50 millimeters per hour to the western regions, including South Chungcheong, South Jeolla and Jeju Island. Heavy rain advisories were issued for parts of South Jeolla and Jeju for Sunday afternoon and for other western areas such as Incheon for Sunday night.

Especially concerning is the overnight period, when downpours of 30 to 50 millimeters per hour are expected across the country, including the capital area. In North Jeolla, Busan and the southern coast and mountainous areas in Jeju, concentrated rainfall could reach up to 80 millimeters per hour — a level considered “extreme rainfall” that could prompt emergency text alerts and heavy rain warnings.

Seoul citizens fill the Cheonggye Stream in central Seoul on July 30 to beat the heat. [NEWS1]

Rainfall is expected to continue through Tuesday morning, with accumulated precipitation in the southern regions possibly reaching up to 250 millimeters. Seoul and the surrounding capital area are forecast to receive between 50 and 100 millimeters, with some areas in Gyeonggi potentially seeing more than 150 millimeters. Regions recently affected by heavy rains remain vulnerable to secondary damage.

“It is especially important to take precautions in areas such as the coastal regions of South Jeolla and South Gyeongsang, where topography and large volumes of southern moisture could cause extremely heavy rain,” said Lee Chang-jae, a KMA forecast analyst.

The incoming rain is expected to temporarily ease or lift heat advisories. In Seoul, temperatures are forecast to peak at 34 degrees Celsius (93.2 degrees Fahrenheit) on Sunday but remain at or below 30 degrees Celsius on Monday.

After the rain subsides, temperatures will likely rise again, causing another spell of sweltering heat. On Wednesday, a band of heavy rain clouds is expected to move south from the north, bringing another round of heavy rain to central regions. Unlike last week, which was dominated by extreme heat, this week the country should brace for extreme rainfall.

“Strong precipitation is forecast to occur in two waves, from Aug. 3 and 4, as well as Aug. 6 and 7,” said Lee. “As large volumes of water vapor continue to flow in, the high humidity and elevated heat index will persist, and people should also prepare for tropical nights.”

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.
BY CHON KWON-PIL [[email protected]]