The heat wave will subside Friday, which marks Chilseok in the lunar calendar, with rain forecast for Jeju.

Chilseok is the time when the heat starts to dwindle and the monsoon season begins.

Due to the influence of Typhoon Rumbia, which is moving northwest from eastern China, rainfall of between 5 and 40 millimeters is expected on Jeju Island.

Skies will be clear in the central region of Korea, but it will be cloudy in the southern part of the country.

The eastern coast of Gangwon Province and the southern coast of South Jeolla Province will see sporadic rain in the morning. The tropical nights that continued for 26 days in Seoul, 27 days in Daejon and 29 days in Yeosu have ended.

Cold and dry air will come into Korea from high pressure in the north, pushing the mercury down to below 25 degrees Celsius in most regions nationwide.

Temperatures at 5 a.m. were 21.8 degrees Celsius in Seoul, 22.8 C in Incheon, 22.4 C in Suwon, 18.1 C in Chuncheon, 18.7 C in Gangneung, 23.3 C in Cheongju, 23.6 C in Daejeon, 24.9 C in Jeonju, 23.8 C in Gwangju, 25.3 C in Jeju, 23.1 C in Daegu, 23.8 C in Busan, 23.6 C in Ulsan, and 23.2 C in Changwon.

By Kim So-hyun (sophie@heraldcorp.com)