What is the definition of plum blossom becoming plum blossom?

A friend asked me if I was in May these days. I said that meteorological significance has specific indicators. The traditional entry and exit of plums is related to heavenly stems and earthly branches. The main basis is as follows

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.

For example, there was a slight summer heat on July 7th 1993, and then it fell on July 13, so the plum blossom date of 1993 is July 13. July 7, 200 1 year is a slight summer heat, and July 19 after the slight summer heat is not an earthly branch. According to the calendar, the plum blossom date of 200 1 should be July 7th instead of July 19.

It is very simple to calculate the chronology of trunk and branch from the known number of years: the number of years MINUS 3, the remainder divided by 10 is the heavenly stem, and the remainder divided by 12 is the earthly branch.