Plum rain falling on june plum clear umbrellas, looking up toward the Tokyo Metropolitan Government Building, in June 2009. In China, the term “plum rain” was used for the rain in the fourth and fifth lunar month.
1700s to the current form of Jangma after 1900s. An east-west zone of disturbed weather during spring along this front stretches from the east China coast, initially across Taiwan and Okinawa, later, when it has shifted to the north, eastward into the southern peninsula of South Korea and Japan. The weather front forms when the moist air over the Pacific meets the cooler continental air mass. The front and the formation of frontal depressions along it brings precipitation to Primorsky Krai, Japan, Korea, eastern China, and Taiwan. The high humidity in the air during this season encourages the formation of mold and rot not only on food but on fabrics as well.
Environmentally, heavy rains encourage mudslides and flooding in all areas affected. June 7 to July 20 in the Kansai and Kantō regions in Honshū. The pop artist Eiichi Ohtaki produced a popular song by this name, and a WW2 Japanese naval ship was also given this name. The rains in the middle of November – early December are sometimes called the sazanka tsuyu, literally “rainy season of the camellia” on account of the timing with the blossoming of the seasonal flower. The rainy season is between June and mid-July. It is caused by hot and humid high pressure forming in the Sea of Okhotsk due to the North Pacific anticyclone combining with Asiatic continental high pressure. Beginning in late-May, the North Pacific high pressure forces the weaker continental anticyclone south of Okinawa Island.
This fall to the south then reverses and gradually strengthens as it moves northwards back towards the Korean peninsula. On landfall, heavy monsoon rains lead to torrential downpours and flooding. By August the system has weakened as the southern systems retreat towards the Filipino archipelago. By early autumn, the North Pacific high-pressure system is pushed away as Asiatic continental cold high pressure moves southwards. This produces inclement weather although not on the scale of the summer monsoons. Korea can, however, be struck by typhoons during this period. In some years, the rainy season’s actual beginning and end are under debate.
The weather front skipped the Chang Jiang region and there was no rainy season there. Then, the ridge retreated southward and there was significant rainfall in the region. Archived from the original on 2013-03-10. 00743 11 40 C 11 55.