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Heat wave ends, monsoons begin: 6 inches of rain to pummel south through Monday

Published: 13 Jul. 2025, 19:28

Tourists walk across rain-soaked ground with parasols at Imjingak in Paju, Gyeonggi, on July 1. [YONHAP]

Heavy rain is expected to sweep across Korea through Monday, with southern regions forecast to receive more than 150 millimeters (5.9 inches), as the powerful heat dome that has gripped the capital area breaks and gives way to unstable weather driven by tropical moisture and northern cold air.

Rainfall began sweeping across the Korean Peninsula on Sunday as a band of rain clouds developed over the Yellow Sea and moved inland, according to the Korea Meteorological Administration (KMA).

“Most areas will continue to see rainfall through Monday, with showers tapering off in the afternoon,” the KMA said.

With the rain, heat advisories that had been in effect nationwide came to an end.

Authorities issued heavy rain alerts, particularly across the southern regions.

The KMA issued heavy rain warnings in areas such as Naju and Jangheung in South Jeolla, where more than 30 millimeters of rain fell per hour, and posted advisories for parts of Gwangju.

The abrupt shift in weather follows the weakening of two high-pressure systems — one over the North Pacific and another over Tibet — that had blanketed the Korean Peninsula.

The collapse of those systems created space for cooler northern air to collide with tropical moisture from the south, resulting in intense rainfall.

While the heat dome triggered widespread heat-related damage in previous weeks, the focus now shifts to preparing for possible flood damage.

The KMA expects rainfall to intensify overnight in southern regions as the 11th tropical depression of the season — which failed to develop into a typhoon — travels northeast through the Korea Strait and into the East Sea.

The system is expected to dump intense rain on southern and eastern coastal areas.

People wait at a crosswalk with umbrellas at Gwanghwamun Intersection in central Seoul on June 20, with a heavy rain advisory in effect across the city. [YONHAP]

The Jeolla region could see downpour of up to 50 millimeters per hour through Monday morning. Total rainfall in southern Korea between Sunday and Monday could exceed 150 millimeters.

“Tropical moisture is tracking toward the Gyeongsang region,” said Gong Sang-min, a senior forecast analyst at the KMA. “In areas where the terrain enhances the effect, rainfall could surpass 50 millimeters per hour. Sudden surges in stream levels are possible in places that have been dry, so please avoid approaching riverbanks or camping near water.”

Rainfall in Seoul is expected to remain relatively light, between 10 and 40 millimeters through Sunday.

While the rain will temporarily ease the heat, humidity levels will keep perceived temperatures high.

Midweek rains are also likely to return to central regions due to another round of cool air descending from the north and moisture pushing northward along the edges of the North Pacific.

“We expect the monsoon rain to mainly impact the central region on Thursday, while southern areas may experience additional rainfall due to terrain effects,” Gong said. “There is still high uncertainty, especially with the possibility of tropical disturbances developing.”

The rain will likely ease the extreme heat that pushed temperatures above 35 degrees Celsius (95 degrees Fahrenheit) last week, but the KMA warned that hot and humid southwesterly winds could gradually raise temperatures again starting Wednesday.

With Chobok — the first of the three hottest days of summer in Korea as recorded by the Lunar Calender — falling on July 20, the return of heat wave conditions remains a possibility by the end of the week.

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