The country experienced three to four more days per year of heat waves and tropical nights for the last decade, compared to the previous 48 years.

The Korea Meteorological Administration(KMA) said on Monday that
there were an average 14 days of heat waves and nine days of tropical nights a year between 2011 and 2020.

This is up three-point-nine days and three-point-three days, respectively, from the averages for 1973 to 2020.

A record 31 days of heat waves were recorded in 2018, followed by 29-point-six days in 1994 and 22 days in 2016. A record 16-point-eight days of tropical nights were posted in 1994, followed by 16-point-six days in 2018 and 14 days in 2013.

A heat wave warning is issued when the maximum day time temperature exceeds 35 degrees Celsius for more than two consecutive days, and an advisory is issued when the high surpasses 33 degrees for two straight days.

A tropical night is classified when the nighttime temperature does not drop below 25 degrees Celsius.