Seoul experienced the first tropical night of the season between Sunday night and Monday morning, when the lowest overnight temperature surpassed 25 degrees Celsius. 

According to the Korea Meteorological Administration on Monday, the temperature hit 25-point-six degrees Celsius in Seoul at its lowest point the previous night.

Last year’s first tropical night in Seoul occurred June 21. 

Tropical night conditions were also observed in Gangneung, Cheongju, Pohang, Daegu, Ulsan, Yeongdeok, Yeongcheon and Seogwipo.

A tropical night refers to a night when the temperature does not fall below 25 degrees Celsius from 6 p.m. to 9 a.m. the following day.

The nation is expected to see sweltering heat on Monday, with temperatures near 33 degrees Celsius forecast for most areas.