Nighttime heavy rain events are intensifying across South Korea as rising sea-surface temperatures and carbon emissions strengthen storms [1], [2].
These nocturnal events present a higher risk to public safety because evacuation and rescue operations are more difficult to execute in the dark [1].
Recent weather patterns highlight the increasing severity of these storms. In southwestern Seoul on Aug. 8, 2022, the area experienced rainfall of 141.5 mm [1]. Some reports indicated the intensity exceeded 140 mm per hour during that event [1]. Reporter Kang Hee-kyung said, "Midcity roads turned into giant rivers in the middle of the night" [1].
The trend continued with a record-breaking event in Seosan, South Chungcheong Province, on July 17, 2025 [2]. This storm was described as the largest historic rain event for the area [2]. The intensity of the 2025 Seosan storm was further marked by extreme electrical activity, with more than 2,500 lightning strikes recorded [1].
Meteorologists link these intensifying patterns to the climate crisis. As the waters surrounding the Korean Peninsula warm, the strength of the rainfall increases [2]. This creates a cycle where higher temperatures provide more energy and moisture for storms to develop, particularly during the night.
A YTN news anchor said, "Heavy rain does not distinguish between day and night, but it is more dangerous when it pours at night because evacuation and rescue are difficult" [1].
“"Midcity roads turned into giant rivers in the middle of the night"”
The shift toward more intense nocturnal rainfall suggests that traditional disaster response frameworks may be insufficient. Because visibility is limited and residents are often asleep, the window for early warning and evacuation is narrowed, potentially increasing casualty rates even if the total volume of rain remains similar to daytime events.
