A pedestrian walks by while covering her face from the sun with a fan in Daegu, as daytime temperatures reached as high as 36 degrees Celsius on Monday. (Newsis)

The weather agency said Monday that it expects the current heat wave to continue at least until Aug. 22, with temperatures until then to record higher than usual.

In the past, Korea saw the summer heat easing into fall weather after Aug. 15. However, due to the continued convergence of the Tibetan and North Pacific high-pressure systems over the Korean Peninsula, the Korea Meteorological Administration anticipates the current heat wave to last longer. Until Aug. 22, morning temperatures are expected to reach up to 27 degrees Celsius while daytime temperatures are expected to range between 30 C and 34 C.

However, as the center of these overlapping high-pressure systems begins to shift this week, the KMA added that the westerly winds that have brought hot and humid temperatures into Korea will shift to still hot but drier easterly winds from this week.

Due to this shift, the national weather agency added that temperatures are expected to rise further in the Greater Seoul area and western parts of Gangwon Province this week. While the heat will continue to be accompanied by more tropical nights, the KMA added that it will be slightly less humid than before due to drier winds.

Eastern parts of Korea, including cities such as Gangneung, Sokcho and Samcheok, can expect to see little relief from the heat this week, with temperatures dropping 1 C to 3 C. However, the KMA added that heat wave warnings and tropical nights may still remain in these areas due to high sea surface temperatures.

Meanwhile, high temperatures will also persist on Tuesday, with apparent temperatures rising to 35 C. Some parts of the country, including the Greater Seoul area, inland regions of Gangwon Province, South Jeolla Province and the Chungcheong Provinces, will see sporadic showers from the afternoon until nighttime.

Across Korea, morning temperatures on Tuesday are expected to range between 22 C and 27 C on Tuesday, while daytime temperatures are expected to range between 30 C and 35 C.

While heat wave warnings were issued nationwide Monday, the tropical night phenomenon has been observed overnight in Seoul for 22 days in a row, the agency said.

According to the KMA, this year's stretch of tropical nights in Seoul is the third longest on record since weather records first began to be kept in the city in 1907.

A tropical night refers to the phenomenon in which the lowest temperature remains above 25 degrees Celsius between 6:01 p.m. the night before and 9 a.m. the next day. As of 8 a.m. Monday, morning temperatures had reached 29.3 degrees C in Seoul.

Other major cities, such as Incheon and Busan, have also been experiencing tropical nights for 20 and 18 days in a row, respectively. The two cities saw temperatures reach up to 29.7 C and 28.8 C as of 8 a.m. Monday.

As of 5:10 p.m., a heat wave warning at the third-highest level of "alert" in the four-tier system, has been issued in most parts of the country, as apparent temperatures ranged between 33 C to 39 C nationwide. Korea issues heat wave warnings at the “alert” level when the highest apparent temperature is forecast to exceed 35 C for two consecutive days or more.