The plum rain is a persistent and extensive rainfall phenomenon that frequently occurs in East Asia during summer, primarily affecting regions along the latitudes of the middle and lower reaches of the Yangtze River in China to the Kyushu Island in Japan. The plum rain is a persistent and extensive rainfall phenomenon that frequently occurs in East Asia during summer, primarily affecting regions along the latitudes of the middle and lower reaches of the Yangtze River in China to the Kyushu Island in Japan. Environment Phys.org – latest science and technology news stories