Extreme summer rainfall in South Korea has shifted toward shorter, more intense downpours as the climate crisis deepens [1].
This transition increases the risk of sudden, severe flooding and infrastructure failure because urban drainage systems are often unable to handle the volume of water delivered in such brief windows.
Recent weather patterns in the Seoul metropolitan area and central regions reflect this trend. During the most recent weekend, extreme rainfall hit the central region and the capital's outskirts [1]. This follows a pattern observed in previous years where the total number of rainy days decreased, but the intensity of the rain when it did fall increased [1].
Data from the Korea Meteorological Administration, which spans a 113-year record, confirms that rainy days are becoming less frequent while precipitation intensity is rising [1]. Professor Son Seok-woo of Seoul National University said that while total precipitation was slightly below average last year and the number of rainy days was historically low, much more powerful concentrated heavy rains were created over short periods [1].
These atmospheric shifts are driven by rising global temperatures. Higher temperatures allow the atmosphere to hold more moisture, which leads to the discharge of massive amounts of water in a concentrated burst rather than a steady rain [1].
The impact of these "extreme rains" has already been felt nationwide. Last year, 15 locations across the country experienced hourly rainfall exceeding 100 mm [1]. Reporter Jo Seong-ho said that these extreme downpours led to successive flooding damages in areas including Gunsan, Seosan, and Sancheong [1].
“"Much more powerful concentrated heavy rains were created over short periods."”
The shift from steady seasonal rains to erratic, high-intensity bursts indicates that South Korea's traditional monsoon patterns are being replaced by volatile weather events. This necessitates a fundamental redesign of urban water management and disaster response strategies, as historical rainfall data no longer accurately predicts the scale of potential flooding.
