Seoul's daytime temperature is expected to soar to 39 degrees Celsius on the 6th, a day before Ipchu, the traditional marker of the start of autumn. Given that the Korea Meteorological Administration's high-temperature forecasts carry an average absolute error of about 1 degree, an unprecedented "40 degrees in Seoul" could become reality.
On Thursday the 6th, morning lows are forecast at 21 to 27 degrees and daytime highs at 30 to 39 degrees. Seoul's morning low was forecast at 27 degrees and its daytime high at 39 degrees. A "39-degree forecast" for Seoul (based on the Seoul Weather Observatory) is a record. Since modern weather observation began in October 1907, Seoul's highest temperature was 39.6 degrees on August 1, 2018. The second-highest was 38.4 degrees on July 24, 1994.
Forecast lows and highs for other major cities are 26 and 38 degrees in Incheon, 26 and 37 degrees in Daejeon and Gwangju, 26 and 36 degrees in Daegu, and 26 and 33 degrees in Ulsan and Busan.
Heat advisories have been issued for most regions, including a top-tier serious heat warning — the highest level of heat advisory — across 31 land-based special weather advisory zones such as 30 zones in the metropolitan area and Gwangyang in South Jeolla and Gwangju. A serious heat warning is issued when the daily maximum apparent temperature has reached 35 degrees or higher for at least two consecutive days recently, and the maximum apparent temperature is expected to reach 38 degrees or higher, or the maximum temperature is expected to rise to 39 degrees or higher. The KMA defined the heat in these areas as life-threatening and urged people to halt or postpone outdoor activities and outdoor work except for essential tasks.
On Friday the 7th, conditions will be similar to the 6th, with morning lows of 22 to 27 degrees and daytime highs of 31 to 39 degrees. Over the weekend, some areas will be cloudy with rain. On Saturday the 8th, morning lows will be 22 to 27 degrees and daytime highs 27 to 36 degrees, and on Sunday the 9th, 21 to 26 degrees and 26 to 34 degrees. Temperatures will drop somewhat compared with before, but will still remain higher than the seasonal average.
After that, a heat wave with apparent temperatures rising to 35 degrees or higher inland and 33 degrees or higher elsewhere is expected to continue until at least Liberation Day.
Typhoon Dolphin, the 13th typhoon, which had been expected to possibly end the heat wave, is now more likely to pass through Okinawa, Japan, and make landfall south of Shanghai, China. Dolphin, which passed 940 kilometers east of Okinawa, Japan, at 3 p.m. on the 5th, is expected to move west with almost no change in direction and make landfall south of Shanghai, China, on the afternoon of the 10th.
While the passage of Dolphin could reshape the pressure systems around Korea, the prevailing forecast is that the heat will not end. As it is still early August, when the North Pacific high-pressure system is at its strongest, Korea is likely to remain under the influence of the North Pacific high even if the pressure systems are reshaped.
