Visitors stroll around Hamdeok Beach on Jeju Island, Saturday. The southern resort island has been experiencing an unusual heat wave for September. Yonhap

The heat wave is continuing despite the passing of traditional seasonal divisions indicating autumn's arrival, as the representative fall holiday, Chuseok, is only a week away.

According to the Korea Meteorological Administration, heat wave advisories were issued in 148 out of 183 regions across the country divided by the agency for weather forecast, as of Monday morning.

Gokseong and Gurye in South Jeolla Province and Uiryeong and Jinju in South Gyeongsang Province had heat wave alerts.

A heat wave advisory is issued when the highest temperature is expected to be 33 degrees or higher for two or more consecutive days or when significant health risks are expected due to a sudden increase in temperature or prolonged heat wave conditions. Heat wave alerts are issued if the daily maximum temperature of 35 degrees Celsius or higher is expected to continue for more than two days.

This is the first time since 2010 Korea has seen heat wave advisories and alerts issued in September.

New records are being set nationwide for the highest temperature in September.

The daytime temperature in Daejeon soared to 34.3 degrees Celsius, Sunday, breaking the record for the highest temperature in September since modern weather observation began in the city in 1969.

Jeongseon of Gangwon Province, Hongseong and Geumsan of South Chungcheong Province, Boeun of North Chungcheong Province, Sangju and Cheongsong of North Gyeongsang Province, Uiryeong of South Gyeongsang Province and Jindo of South Jeolla Province also set new daily temperature records in September.

The weather agency predicts that the current heat will continue at least until the Chuseok holiday that falls from Sept. 16 to 18.

According to the forecast for the highest temperatures in Seoul, the daily high will remain at 29-31 degrees from Thursday to Sept. 16. The temperature will start dropping over Chuseok, but it will remain at around 28 degrees, higher than usual autumn mercuries.

Moreover, it is difficult to confirm a relief from heat to come after the Chuseok holiday, as Tibetan high pressure shows no signs of contraction.