Heatwave reaching 'highest temperatures' until Chuseok... Cooling expected from the weekend

Seoul Issues 'Latest Heatwave Warning' Across the City
Temperatures Drop Nationwide with Rain on 20th-21st

The heatwave-level heat continues through the last day of the Chuseok holiday. Due to the unprecedented 'Chuseok heatwave,' heatwave warnings have been issued in most regions nationwide. The heat will persist until the first working day after the holiday, the 19th, and is expected to gradually subside as rain falls across the country on the 20th.

As of 3 p.m. on the 18th, heatwave warnings were issued in 166 out of 183 weather advisory zones nationwide, accounting for 91%. There are 125 areas under heatwave alerts and 41 under heatwave watches.

On the afternoon of the 18th, when a heatwave warning was in effect, citizens visiting Eulwangri Beach in Jung-gu, Incheon, were cooling off from the heat. [Image source=Yonhap News]

In Seoul, the heatwave watch in the southwestern area was upgraded to a heatwave alert at 10 a.m., and by 2 p.m., heatwave alerts were in effect across all remaining areas. The heatwave alert in Seoul in September was the first since the introduction of the heatwave advisory system in 2008, occurring on the 10th. This alert is considered the 'latest-ever heatwave alert in Seoul.'

Several southern regions recorded the highest temperatures ever observed in September since local weather observations began, including Tongyeong in Gyeongnam (34.6°C as of 2 p.m.), Gimhae (36.9°C), Yangsan (37.2°C), Jeongeup in Jeonbuk (36.5°C), and Yeonggwang in Jeonnam (35.3°C). Jeju (34.8°C) and Jeonju in Jeonbuk (35.2°C) recorded the second-highest September temperatures on record that day.

Even Daegwallyeong in Gangwon, known as one of the coolest areas nationwide, saw temperatures rise close to 30°C, reaching 29.7°C. This is the second-highest September temperature recorded in Daegwallyeong's history.

These records are based on data as of 2 p.m. Since the highest temperatures of the day are usually recorded between 3 and 4 p.m., more regions may show 'record-breaking temperatures' later that day.

New records were also set on Chuseok day. The lowest temperature overnight in Seoul was 26.5°C, 9.2°C higher than the average, breaking the record for the 'latest tropical night.' Incheon and Daejeon also experienced their latest tropical nights on record, similar to Seoul. In Jeju, the total number of tropical nights this year increased to 72, including the overnight tropical night.

On the 9th, Seoul experienced its latest tropical night on record as temperatures remained above 25 degrees Celsius. On the afternoon of the 10th, when a heatwave warning was issued across Seoul, citizens watched the fountains at Yeouido Hangang Park in Yeongdeungpo-gu, Seoul.
[Image source=Yonhap News]

Currently, a high-pressure system with high temperatures is positioned in the upper atmosphere over the Korean Peninsula. Hot and humid southeasterly winds continue to blow between the high-pressure system moving from northeastern China to the East Sea and the low-pressure system south of Korea, including Typhoon Pulasan (No. 13). This heat will continue at the current level until Thursday, the 19th.

The morning low temperatures on the 19th will range from 22 to 27°C, and daytime highs will be between 28 and 36°C. Afterward, a trough will move southward from the north on the 20th, bringing rain nationwide until the 21st. Rain will continue in Gangwon Yeongdong, southern regions, and Jeju until the 22nd, easing the heatwave. This is due to the inflow of cold air behind the rain and trough.

The morning low temperatures on the 20th are expected to be 22 to 27°C, with daytime highs between 26 and 31°C. Although still higher than average, daytime temperatures will be lower compared to the 19th. Over the weekend, temperatures will drop further, with morning lows of 17 to 25°C and daytime highs of 21 to 29°C.