People walk outside under strong sunlight at Gwanghwamun Square in Seoul on Wednesday. (Yonhap)
People walk outside under strong sunlight at Gwanghwamun Square in Seoul on Wednesday. (Yonhap)

A heat wave warning was issued for all of Seoul on Thursday, putting the capital city back under the highest-level heat notice for the first time in 11 days, the state weather agency said.

A heat wave warning is issued when the maximum apparent temperature is expected to remain above 35 C for two or more days or the heat is expected to cause large-scale damage, according to the Korea Meteorological Administration.

The warning took effect for Seoul at 10 a.m.

Previously a heat wave warning was in place over Seoul from July 7-13, when the notice was brought down a notch to an "advisory," which is issued when the maximum apparent temperature is forecast to remain above 33 C for at least two consecutive days.

Of the 183 weather zones on land, 126, or 69 percent, are currently under a heat wave warning, while 51 (28 percent) are under a heat wave advisory, the KMA said.

The maximum temperature Thursday is expected to range from 32 C to 36 C.

On Friday, it is set to range from 31 C to 37 C; on Saturday, 32 C to 38 C; and on Sunday, 31 C to 37 C. (Yonhap)