Jeju to Start 'Monsoon' from 19th to 20th... Heatwave Continues in Central Regions

Jeju Mountain Area Receives Over 200mm of Rainfall

The Korea Meteorological Administration (KMA) announced that the summer monsoon will begin from Jeju late at night on the 19th or early dawn on the 20th.

Layers of clouds in different colors are gathering over Seoul.
Photo by Jo Yongjun

According to the KMA on the 18th, the northwestern edge of the North Pacific High has advanced northward to around 30 degrees north latitude, forming a stationary front over southern Japan and inland southern China. In inland southern China, a trough has developed along the stationary front and is slowly moving eastward. The timing of precipitation depends on the movement speed of the trough, which can change at any time with support from the upper-level trough in the northwest atmosphere.

Rain in Jeju is expected to continue until dawn on the 21st. On the afternoon of the 20th, the stationary front will move northward close to Jeju, bringing heavy rain with hourly precipitation of 30 mm. The total expected rainfall is 50 to 100 mm. In many areas, more than 150 mm is expected, and in the mountainous areas of Jeju, total rainfall is forecast to exceed 200 mm.

Some parts of the southern regions may also experience rain. Expected rainfall amounts are 5 to 20 mm along the southern coast of Jeollanam-do, 5 to 10 mm along the southern coast of Gyeongsangnam-do, and around 5 mm in southern Jeollabuk-do, Busan, Ulsan, and inland Gyeongsangnam-do. The KMA stated, "Although some rain may fall in the southern regions starting from the 20th, since the stationary front will be located near Jeju or south of Jeju after the rain, continuous rain in the southern regions is unlikely, so we do not plan to declare the start of the monsoon in the southern regions."

The northern boundary of the North Pacific High will extend southward to the south of Jeju from the 22nd to the 24th, bringing rain again to Jeju. The precipitation areas depend on the stationary front formed by the interaction between the North Pacific High and dry air moving southward from a low-pressure system passing north of Korea.

Based on the average year, the monsoon ends on July 20 in Jeju, July 24 in the southern regions, and July 26 in the central regions. The average number of rainy days during the monsoon season is 17.0 to 17.7 days.

Meanwhile, the central regions will continue to experience heatwaves, and heatwave warnings issued mainly for inland areas are expected to gradually expand.

This content was produced with the assistance of AI translation services.