What is the rain in May?

In early summer, there are often long rainy days in the Jianghuai basin. At this time, the utensils are easy to be moldy, so it is also called "moldy rain" or "mildew" for short; It is also called "Plum Rain" or "Huang Meiyu" because plums in the south of the Yangtze River are yellow and ripe. It is recorded in China's historical records. For example, The Book of Beginners quoted the compilation of Emperor Liang Yuan in the Southern Dynasties, "Plum blossoms have plum rains when they are ripe". Liu Zongyuan's Plum Rain in the Tang Dynasty: "Shi Mei welcomes the rain, and it is invaluable in late spring." Wait a minute. It is recorded in China's almanac that there is mildew rain all day: it is called "mildew" at the beginning and "mildew" all day long. The first day after the awn is planted, it will be moldy, but it will not be moldy on the first day after the light summer. Mold always enters between June 6~ 15 and leaves between July 8~ 19. There is an obvious rainy season in eastern China, with a long rainy period and relatively concentrated rainfall, which is caused by the displacement of the main rain belt from east to west to north, and is a unique phenomenon in the turn of atmospheric circulation in East Asia at the turn of spring and summer. After mid-June, the rain belt remained in the Jianghuai basin, which is Meiyu. "(However, because the current language is a habitual language, the plum rain mentioned now is not limited to the Jianghuai valley to Japan, and the continuous precipitation in the eastern part of China, such as Fujian, during the plum rain season is also called plum rain. )

The time that the rain belt stays is called "Meiyu season", the day when the rainy season begins is called "entering the plum blossom", and the day when it ends is called "emerging the plum blossom".

In addition, due to the high humidity in the air during this period, everything is easy to be damp and moldy, so people gave Meiyu an individual name, called "Moldy Rain". Xie Zaihang's Five Miscellaneous Torches in Ming Dynasty? 6? 1 Tianbu No.1 describes: "Every year in March and April in the south of the Yangtze River, it rains bitterly, and everything is moldy, commonly known as plum rain, and plums are covered when they are green and yellow. From Xu Huai to the north, it is often dry in spring and summer. By the turn of June and July, it was raining heavily and everything was moldy. "Li Shizhen, an outstanding medical scientist in Ming Dynasty, clearly pointed out in Compendium of Materia Medica:" Plum rain or mildew rain, when it comes to clothes and things, will produce black mold. ".