A joint study by KAIST and the Asia-Pacific Climate Center found that East Asian summer fronts have shifted northward, bringing late-summer rain bands closer to southern Korea. Comparing 1979-1998 with 2006-2025, researchers found the front moved about 213 kilometers north during September 10-30, when heavy rain and heat exposure rose together.
Years with a northern late-summer front saw simultaneous above-normal rainfall and heat occur 8 to 19 times more often than years with a southern front, even after removing long-term climate trends. The researchers said flood prevention and heat-illness response should be planned as one combined risk for September.