Temperatures soared to record highs in southeastern parts of South Korea on Wednesday, with Busan reporting an all-time high in 122 years, as a sweltering heat wave gripped the nation.

The southeastern city of Yangsan reached 40.3 C at 3:34 p.m. -- the highest since 2008, when the state weather agency began collecting weather data in the city -- according to the Korea Meteorological Administration (KMA).

The city had previously logged 39.3 C on Sunday, matching the previous record set in 2024.

Temperatures in the nearby port city of Busan stood at 38.8 C at 2:56 p.m., surpassing the previous record of 37.3 C in 2016 to mark the highest since weather tracking for the city began in 1904.

The agency attributed the heat wave to the dual influence of the North Pacific High and the Tibetan High pressure systems, projecting the heat wave to persist through the end of next week.

Earlier in the day, the KMA upgraded a heat wave advisory to a full warning for eastern and southwestern parts of Seoul, marking the capital's second heat wave warning this summer.

A heat wave warning is issued when the maximum apparent temperature is expected to remain above 35 C for two or more consecutive days.

The apparent temperature reached 35.1 C in southern Seoul at 3 p.m., according to the KMA.

In response, the Seoul metropolitan government has opened local administrative offices for the public to use to cool off around the clock.

The city has also restricted outdoor work from 2 to 5 p.m. at municipal construction sites, recommending private construction sites to do the same.