What does "entering the plum blossom" mean in the old imperial calendar? Please help me solve it.

What does it mean to be a plum blossom?

What does it mean to be a plum blossom? Also known as "into the mold" and "into the plum blossom". Refers to the day when the rainy season begins. Song Luyou's poem "Into the Plum": "Light rain and light clouds enter the Plum, and pomegranate and day lily bloom for a while." Huang Meiyu in Summer by Chen Yuanyuanliang: The Outline of the Four Seasons says,' Plum rains when the plum is ripe'. "In addition, Fujian people regard Geng Ri of Xia Hou as plum blossom, and Ren Ri after Mang Zi as plum blossom. Wen Wei Po 1984.5.2 1: "Therefore, we should listen to the plum rain forecast released by the Meteorological Observatory, instead of using the plum blossom in the calendar to guide our production and life."

Because there was no accurate weather forecast in ancient times, people needed to know the flowering time of plum blossoms, so they needed to determine an approximate date. 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.

In ancient China, there were several rules for entering Mei. In trivial records, "(Min people) entered Mei on Geng Day in Xia Hou." "Shenshu Jing": "After the awn is planted, it will enter the plum in three days." "Jiangnan Record": "Plant mangoes in May, and meet your wife and enter Mei." "Tian Wu Jia Xing": "The rain after the awn seed is Huang Meiyu", and the awn seed is considered as plum blossom. There are two reasons for the above differences: first, regional differences; Second, the date of entering Mei for many years often changes. At present, in the almanac of our country, the saying of Shenshu Jing is adopted. In the weather analysis and forecast, it often refers to the day when the weather situation turns to Meiyu situation.