The Japan Meteorological Agency said Wednesday morning that the rainy season has ended in northern Kyushu, the Chūgoku region, and the Kansai region [1].
This abrupt transition to summer increases the immediate risk of heat-related illnesses as temperatures climb rapidly across southern and western Japan. The shift has forced local governments to implement emergency health warnings to protect residents from extreme heat.
According to the agency, the rainy season ended 11 days earlier than the climatological average [1]. Preliminary data indicates the rainy season lasted for 34 days [2].
This early departure of the rains has coincided with a surge of "true-summer days," characterized by high temperatures. Prefectural governments have issued heat-stroke alerts for six prefectures, with a primary focus on the Kyushu area [1].
Forecasts show significant heat in specific urban centers. The Japan Meteorological Agency said a high of 36 degrees Celsius was forecast in Kurume City, Fukuoka Prefecture [1]. Similarly, Hita City in Oita Prefecture was expected to reach 35 degrees Celsius [1], following an observed high of 34 degrees Celsius [1].
Local authorities are urging citizens to take precautions against heat stroke as the regions transition into the peak of summer. The agency said the rapid rise in temperature follows the early disappearance of the seasonal rain belts that typically stabilize temperatures during this period [1].
“The rainy season ended 11 days earlier than the climatological average.”
The premature end of the rainy season suggests a volatile transition into the summer months, potentially intensifying the severity of Japan's heatwaves. When the rainy season ends significantly early, the lack of soil moisture and cooling precipitation can lead to a more rapid increase in ambient temperatures, placing higher stress on public health infrastructure and energy grids in the affected prefectures.
