Heavy Rain Mainly in the Seoul Metropolitan Area This Week... Hot and Humid Late Summer Heat Next Week

The solar term Cheoseo (23rd), which signifies the end of the heatwave, is just two days away, but the intense heat continues to rage, especially in the Seoul metropolitan area where heatwave warnings have been in effect for over a week. Although heavy rain is forecast nationwide this week, which will temporarily ease the heat, the late summer heat is expected to return once the rain stops.

According to the Korea Meteorological Administration, scattered showers are expected across the country starting from the afternoon of the 21st. Between 6 PM and 9 PM, rain is forecast on Jeju Island, and from 9 AM to midnight, showers are expected in the Seoul metropolitan area, Gangwon Province, Chungcheong region, Jeolla region, inland Gyeongbuk, and northwestern inland Gyeongnam. Particularly, very strong showers accompanied by gusts of wind, thunder, and lightning with hourly rainfall of 30 to 60 mm are expected mainly in the central inland areas. Although cloudy skies are anticipated nationwide, daytime high temperatures will remain high, ranging from 28 to 34 degrees Celsius. The heatwave warnings issued nationwide are also likely to remain in effect at least until that day. The combination of high temperatures and increased humidity will raise the perceived temperature. Currently, heatwave advisories have been issued since the 13th in most areas of Seoul, Incheon, and Gyeonggi Province, with some parts of Gyeonggi under heatwave warnings.

Starting from the 22nd, the nature of the rain will change, and the heatwave is expected to temporarily subside. Until now, the rain has been localized heavy showers caused by atmospheric instability, but as the Korean Peninsula enters the influence of a low-pressure system, there is a growing possibility of developing raincloud bands capable of producing prolonged heavy rainfall. A pressure trough connected to a northern low-pressure system will pass through northeastern China on the 22nd, forming a long raincloud band from North Korea to Shanghai, China. Southwest winds will blow in front of this trough, bringing large amounts of moisture into the Korean Peninsula.

Accordingly, heavy and widespread rain is expected, especially in the Seoul metropolitan area. The expected rainfall on the 22nd is ▲ 20-60 mm in Seoul, southern Gyeonggi, and northern inland Gangwon ▲ 30-80 mm in Incheon and northern Gyeonggi ▲ 10-50 mm in central and southern inland Gangwon, central and northern Gangwon mountains, Daejeon, Sejong, Chungnam, Chungbuk, Gwangju, Jeonnam, and Jeonbuk ▲ 10-50 mm on Jeju Island. This rain is expected to continue into early next week. The Korea Meteorological Administration forecasts rain nationwide until the 28th-29th. A meteorological official explained, “If the low-pressure system originating in inland China slowly passes over the Korean Peninsula, strong and heavy rain could occur nationwide,” adding, “The movement path of the low-pressure system may vary depending on the extent of expansion of the North Pacific high-pressure system, which has currently retreated east of the Korean Peninsula.”

However, after this rain ends, the heat is likely to return. There are no other factors besides the rain that would cause temperatures to drop. The Korea Meteorological Administration expects that after the raincloud bands move away at the end of this month, morning temperatures will be between 21 and 25 degrees Celsius, and daytime temperatures will range from 27 to 32 degrees Celsius, which is similar to or slightly higher than the average (normal minimum temperatures 19-23 degrees Celsius, maximum temperatures 27-30 degrees Celsius).

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