Seoul and the surrounding capital region are under a major heat warning as temperatures are forecast to reach 38 °C this Wednesday [1], [2].

The prolonged heatwave poses significant public health risks because the city has experienced two consecutive weeks of tropical nights [1]. When nighttime temperatures remain high, the human body cannot recover from daytime heat stress, increasing the likelihood of heat-related illnesses across the region.

Authorities have triggered the ‘중대경보’ — the highest-level heat warning — for Seoul, Jeonju, and parts of Honam [1], [2]. This alert follows a period of intense heat where Seoul recorded a daytime high of 36.9 °C on Tuesday [2].

Weather conditions have been particularly severe during the overnight hours. The nighttime low reached 29.1 °C, which is nearly 30 °C [2]. This level of warmth is characterized as an "ultra-tropical night" by meteorologists.

"Seoul has already seen tropical nights persist for two consecutive weeks," Won Yi-da, a YTN weather caster, said [2].

Humidity has further complicated the heat. The apparent temperature was reported to be nearly 31 °C [1]. This discrepancy between actual and felt temperature increases the risk of heatstroke, and dehydration for residents in the capital region.

"Yesterday, the daytime temperature in Seoul recorded 36.9 degrees, and today it will soar to 38 degrees, making it even hotter," Won said [2].

The forecast indicates that the intense heat will continue to affect the broader capital region and the Honam area, maintaining the high-alert status for emergency services and public health officials [1], [2].

“Seoul has already seen tropical nights persist for two consecutive weeks”

The activation of the ‘중대경보’ (major heat warning) signifies a critical threshold where standard cooling measures may be insufficient. The combination of 'ultra-tropical nights' and extreme daytime highs prevents the urban environment from cooling down, creating a compounding heat effect that places extreme stress on the electrical grid and vulnerable populations.