South Korea recorded its highest number of tropical nights on record in 2026, with a nationwide average of 7.1 days [1].
This surge in nighttime temperatures marks a significant shift in regional climate patterns, impacting public health and sleep quality across the peninsula. The increase reflects a growing trend of extreme summer weather that exceeds historical norms.
Weather monitoring agencies tracked the data across 62 observation sites [1]. The period analyzed spanned from May 2026 through July 26, 2026 [1]. During this window, the national average of 7.1 days [1] surpassed the previous record of 6.5 days established in 1994 [1]. This figure represents an increase of 1.2 days compared to the same period last year [1].
Tropical nights are defined as nights where the minimum temperature remains at or above 25 degrees Celsius, Reporter Kim Seung-hwan said [1].
Regional disparities were prominent in the data. Jeju recorded the highest regional average with 17.8 days [1]. The Gwangju and Jeonnam regions followed with 13.7 days [1], while the Seoul, Incheon, and Gyeonggi areas averaged 5.7 days [1].
Meteorologists attribute the spike to a combination of an early end to the monsoon season and an intense heat wave [1]. This "steamer-like" heat led to unusually high nighttime temperatures that prevented the land from cooling.
"Many people must be unable to sleep properly due to the recent steamer-like heat," an anchor for YTN News said [1].
These figures represent the highest levels recorded since observations began in 1973 [1]. The data indicates that the intensity of summer heat is no longer just a daytime phenomenon but is increasingly extending through the night.
“South Korea recorded its highest number of tropical nights on record in 2026.”
The breach of a 30-year-old record from 1994 suggests that South Korea is experiencing a structural shift in its summer climate. When nighttime temperatures fail to drop, the human body cannot recover from daytime heat stress, which typically increases the risk of heat-related illnesses and elevates energy demand for cooling systems. The extreme variance between Jeju's 17.8 days and the capital region's 5.7 days also highlights how geography and humidity are amplifying the effects of global warming differently across the peninsula.
