As the monsoon rain that drenched many parts of the country eases, sweltering heat is moving in right away. After the rain stopped, humidity stayed high while temperatures rose quickly, prompting additional heat advisories for parts of southwestern Seoul, Gwangju, Daejeon and other areas nationwide. On Saturday the 11th, daytime highs will climb to 37 C, and most regions are expected to see tropical nights.
According to the Korea Meteorological Administration on the 10th, rain will fall through the morning in the Chungcheong region, western North Jeolla, the South Jeolla west coast, and inland areas of northern and central North Gyeongsang, and some spots in the greater Seoul area, Gangwon Province and Jeju Island will see rain through the daytime. Northern Gyeonggi and inland areas of central and northern Gangwon also have a forecast chance of heavy rain of about 20–30 mm per hour through the morning.
However, as the rain clouds gradually weaken, the heat is returning. The Korea Meteorological Administration issued a heat advisory at 10 a.m., effective from 11 a.m. Newly added to the advisory are parts of southwestern Seoul; parts of Gyeonggi; parts of the Gangwon east coast; parts of Chungcheong, Honam and Yeongnam; and Gwangju and Daejeon.
By area, heat advisories took effect in Yangju, Osan, Pyeongtaek, Anseong and eastern Yangpyeong in Gyeonggi; the Donghae plain, Samcheok plain and Gangneung plain in Gangwon; Nonsan and Geumsan in South Chungcheong; Okcheon, Yeongdong, Jecheon, eastern Cheongju and western Cheongju in North Chungcheong; and Damyang, Jangseong, Hwasun, Boseong, Yeosu, Suncheon, Jangheung, Gangjin, Yeongam, Hampyeong, Mokpo, Sinan, Jindo, Yeonggwang, Naju, Gokseong, Gurye, Goheung, Haenam and Muan in South Jeolla. Most areas of North Jeolla Province, Sangju, Cheongsong and northern Andong in North Gyeongsang, Sacheon and southeastern Sancheong in South Gyeongsang, southwestern Seoul, Daejeon and Gwangju were also included.
From this day, daytime temperatures in most regions nationwide will rise to 30 C or higher. The maximum heat index will climb to around 31 C, and in areas under heat alerts it will rise above 33 C. Daytime highs are forecast at 28–34 C.
The heat is likely to intensify toward the weekend. On the 11th, morning lows will be 21–26 C and daytime highs will rise to 29–37 C. On the 12th, morning lows will be 23–26 C, and daytime highs are expected to soar to 30–38 C. As temperatures will not drop enough overnight, some areas nationwide may experience tropical nights.
There remains a chance of showers even after the rain stops. From morning to afternoon, showers are possible in inland western South Gyeongsang, and from afternoon to evening, in northern and southeastern Gyeonggi, inland and mountainous Gangwon, the Chungcheong region, and inland northern North Jeolla. Expected rainfall is 5–40 mm in northern and southeastern Gyeonggi, inland and mountainous Gangwon, the Chungcheong region, and inland northern North Jeolla, and 5–20 mm in inland western South Gyeongsang.
The Korea Meteorological Administration said that in areas with showers, heavy rain of 20–30 mm per hour may pour down with gusty winds, thunder and lightning, and urged caution regarding facility management and safety accidents. In areas where the ground has weakened due to recent heavy rain, caution is also needed for additional damage such as landslides, retaining wall collapses, river flooding and underpass isolation.
In areas under heat alerts, outdoor activities at midday should be minimized and plenty of fluids should be taken. Older adults, people with chronic illnesses and outdoor workers, in particular, face a higher risk of heat-related illness, so they should avoid daytime work and secure sufficient rest time.