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Gov't overhauls weather alerts as 'extreme heat' becomes new normal
A man pours water over his head to cool off from the sweltering heat in Jongno, Seoul, July 29, 2025. Yonhap
By Lee Kyung-min
For decades, the arrival of summer in Korea was heralded by the rhythmic hum of cicadas and the predictable onset of monsoon season. But as climate change rewrites the country’s seasonal script, the government is bracing for a new reality.
The Korea Meteorological Administration announced a sweeping overhaul of its national weather warning system Wednesday, the first major restructuring in nearly two decades. The centerpiece of the plan is the introduction of a top-tier “extreme heat emergency” alert — the result of a decade in which scorching afternoons, sleepless "tropical nights" (a meteorological phenomenon where the temperature remains at or above 25 degrees Celsius, or 77 degrees Fahrenheit, between 6:01 p.m. to 9 a.m. the following day) and record-breaking torrential downpours have moved from anomalies to the new seasonal baseline.
Under the new protocol, which takes effect June 1, the weather agency will move beyond the two-tiered advisory system established in 2008. "Extreme heat emergency" will be triggered when the daily perceived temperature is forecast to hit 38 degrees Celsius, or when actual mercury readings are expected to eclipse 39 degrees Celsius. It is a threshold designed to signal a shift from discomfort to a legitimate threat to public health and infrastructure.
The weather agency’s data paints a stark picture of a peninsula in flux.
Over the past five years, the average number of heat wave days and tropical nights has surged nearly threefold compared to the 1970s. The frequency of intense rainfall, with deluges exceeding 50 millimeters per hour, has also tripled, often turning urban streets into flash-flood traps.
To combat this, the weather agency is also introducing an emergency text alert for catastrophic rainfall approaching 100 millimeters per hour, localized at the township level to prevent the "alert fatigue" of citywide warnings. Additionally, a new tropical night advisory will warn residents when overnight lows are forecast to remain dangerously high in areas already baking under daytime heat.
"The climate we knew 20 years ago no longer exists," the agency said in its briefing. Additionally, by expanding its forecasting zones from 183 to 235 regions, the government hopes that more granular data will allow local officials to deploy disaster responses with the speed that a warming world now demands.
This article was published with the assistance of generative AI and edited by The Korea Times.