Rain-bearing weather fronts have shifted northward across East Asia as the climate changes, raising the risk of late-season heat and torrential downpours, according to a new study.
Researchers at the APEC Climate Center (APCC) and the Korea Advanced Institute of Science and Technology (KAIST) said on the 24th that their findings were published in npj Climate and Atmospheric Science, an international journal. The team used reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) covering 1979 to 2025 to track changes in the position of East Asian fronts over 47 years.
During the 2006-2025 period, the front in the mid-stage of the summer monsoon season — from late June through July — formed about 1.32 degrees of latitude, or roughly 146 kilometers, farther north than in the preceding two decades. The shift was larger from the 10th to the 30th of September, when the central axis of the front moved about 1.92 degrees, or 213 kilometers, northward. A front is the boundary where cold air meets warm, humid air. As hot and humid air flows in along the front and rises, rain clouds develop and heavy downpours follow. Fronts typically advance toward the Korean Peninsula in summer and retreat south in September, but in recent years they have lingered near the peninsula for longer periods.
The team also analyzed wet bulb globe temperature (WBGT), a measure of heat risk that combines temperature, humidity and solar radiation. The analysis showed a growing risk that severe heat will occur at the same time as torrential rain. "Summer disasters are extending later into the year because of climate change, so we need a response system for this and an integrated disaster management strategy that prepares for heat waves and heavy rain together," the researchers said.
Meanwhile, Jeju Special Self-Governing Province was hit by heavy rain and strong winds on the same day. According to the Jeju Regional Meteorological Office, 139 millimeters of rain fell at Witsaeoreum on Mount Halla from the previous day through 8 a.m. on the 24th, along with 126.5 millimeters at Samgakbong and 121 millimeters at Sajebi. Coastal areas recorded rainfall around 100 millimeters, including 113 millimeters in Pyoseon and 106.2 millimeters in Seongsan. Strong wind advisories were in effect for inland Jeju and Chuja Island. The weather agency forecast additional heavy rain of 20 to 30 millimeters per hour through the 25th. Flights were operating normally, though some ferry services were canceled.
The weather agency warned ships to exercise caution, saying strong winds and waves of more than five meters could develop in waters off Jeju from that night. It advised people to stay away from the coast, where swells could wash over rocky shores and breakwaters, and said facilities and crops inland should be secured against winds of more than 20 meters per second through the morning of the 26th.