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Korea's monsoon season to begin Thursday in Jeju with rain set to move north

Published: 11 Jun. 2025, 17:19 Updated: 11 Jun. 2025, 18:00

Heavy rain hits pedestrians walking by Seoul Station in Jung District, central Seoul, on May 16. [YONHAP]

Korea will enter the summer monsoon season on Thursday, beginning with rain over Jeju Island. This is a full week earlier than usual and marks the third-earliest start on record since 1973.

Early monsoon arrival

A stationary front lingering south of Jeju is expected to move northward overnight, bringing the first bouts of monsoon rain to the island starting early Thursday, the Korea Meteorological Administration (KMA) said Wednesday.

Typically, the rainy season in Jeju begins around June 19. This year’s early onset follows previous early starts in 2011 and 2020, both of which began on June 10.

The KMA attributes the accelerated timing to the early expansion of the North Pacific high-pressure system, which has pushed the stationary front up toward the Korean Peninsula. Rainfall totals in Jeju through Thursday are projected to range between 20 to 60 millimeters (2.4 inches), with some areas receiving over 80 millimeters.

A Cheollian weather satellite image taken by the Korea Meteorological Administration on June 12 shows a long band of clouds forming a stationary front south of the Korean Peninsula. Fragments of cloud systems that failed to develop into a typhoon are visible east of the Philippines. [KOREA METEOROLOGICAL ADMINISTRATION]

Nationwide rain

Beginning Friday, rain will gradually spread from the southern regions through to the central parts of the country, as the stationary front shifts eastward. The KMA explained that this movement will open a channel for tropical moisture to flow north from the Philippines.

This influx stems from a tropical disturbance east of the Philippines, which failed to develop into a typhoon but will still supply significant moisture to the peninsula.

As a result, southern and central provinces — including the Chungcheong regions — will see rainfall from Friday, with showers expected to reach Seoul and most other regions by Saturday.

Heavy rain advisories may be issued for areas like Jeju and the southern coast, where rainfall is forecast to intensify.

“It’s critical to prepare, especially in Jeju, the southern regions and parts of Chungcheong, where intense rain is likely due to the tropical moisture coming from the east of the Philippines,” said Woo Jin-kyu, a spokesperson at the KMA.

However, the agency noted that because the rain in the central and southern regions may not persist in typical monsoonal patterns, an official declaration of the monsoon season may not extend beyond Jeju for now.

Pedestrians cross a street in Daegu on June 11. [YONHAP]

Typhoon unlikely to strike, may add rainfall

Typhoon Wutip, the first named storm of the year, adds further complexity to the weather pattern.

It formed around 10 a.m. Wednesday, about 580 kilometers (360 miles) east of Da Nang, Vietnam. With a central pressure of 994 hectopascals and maximum wind speeds of 18 meters per second (40.2 miles per hour), Wutip has a wind radius of approximately 260 kilometers.

Wutip — named by Macau and meaning “butterfly”— is expected to move slowly northward and strengthen into a mid-range Category 2 typhoon before making landfall in southern China around Saturday.

While Wutip is unlikely to have a direct impact on Korea, its remnants may influence weather here. The KMA stated that residual moisture from the storm could flow into Korea after Wutip weakens into a tropical depression over China between Sunday to Monday.

If that moisture interacts with cold air descending from the north, it may trigger another round of heavy rain during the same period.

“There is significant uncertainty around rainfall timing and distribution depending on when and where the typhoon dissipates and how strong the cold air mass is,” said Gong Sang-min, a forecasting analyst at the KMA. “However, areas where warm, humid air clashes with colder air are likely to experience substantial rainfall.”

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