As heat wave advisories have been issued for the capital area and most of the southern Jeolla and Gyeongsang Provinces on Sunday, the heat index in those regions is forecast to surpass 33 degrees Celsius.

According to weather authorities, daytime highs nationwide will range from 27 to 33 degrees.

Showers of up to 20 millimeters, accompanied by gusts of wind, thunder and lightning, are expected in the southern parts of Gangwon Province, the inland areas of the central Chungcheong Provinces, and the southern Jeolla, Gyeongsang and Jeju regions.

Similar conditions are expected for Monday, with showers of up to 20 millimeters forecast for the northwestern areas of Gyeonggi Province, the eastern parts of Gangwon Province and the southern regions.