What's the date of a bad day?

The mold will enter from June 6th to 15, and will be released from July 8th to 19. There is an obvious rainy season in the eastern part of China, with a long rainy period and relatively concentrated rainfall, which is caused by the north-south displacement of the main rain belt in the east-west direction and is a unique phenomenon in the seasonal transformation of the 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. The time for rain belt to stay is called rainy season, the day when rainy season begins is called plum blossom, and the day when rainy season ends is called plum blossom.

Traditionally, in China, the judgment of plum entry and plum exit is based on the combination of solar terms and branches. According to the calendar, the first third day after mango seeds is plum blossom, and the first last day in Xia Hou is plum blossom. If the weather on the awning day is C, it is designated as entering the plum blossom, and if it is not in the shallow summer, it is designated as leaving the plum blossom.

Causes of climate formation

The formation of Meiyu is the result of long-term stagnation of cyclones or fronts in the local area. During May and June of each year, the subtropical high in the western Pacific is rapidly strengthened, and the hot and humid tropical marine air mass and equatorial air mass expand to Nanling area of China, and contact with the cold temperate air mass from the north to form a front. On the front, cyclones or troughs are constantly produced. When these cyclones or troughs move eastward, they are often blocked by the high pressure along the coast of China, so they move slowly.

Long-term detention in the southeast hills, the middle and lower reaches of the Yangtze River and the southern part of the Huaihe River basin has caused continuous rain and plum rains. From the meteorological point of view, the judgment of "entering Mei" needs to consider the actual weather (precipitation) and the configuration of atmospheric circulation. At present, in the weather forecast business of various provinces and cities, the dates of plum blossom and plum blossom are mainly determined by local rainy days, rainfall, temperature and the location of subtropical high. If they meet their respective standards, it means that plum blossoms enter (exit).

The above contents refer to Baidu Encyclopedia-Meiyu Period.