Most of South Korea remains under a heat advisory for the sixth straight day as sweltering temperatures and high humidity continue to grip the nation.

The Korea Meteorological Administration forecasts that afternoon highs Thursday will reach 34 degrees Celsius in Gwangju, 32 degrees in Daegu and 31 in Seoul and Daejeon.

The weather agency said temperatures will continue to surpass 30 degrees Celsius until early next week, and it is urging the elderly to pay extra attention to their health under these conditions.

Escaping the heat has been problematic as well. The weather service said the tropical night phenomenon in which nighttime lows stay above 25 degrees Celsius persisted in Jeju Island and the southern regions on Wednesday.