How to calculate the starting date of counting volts and counting nine

There is a saying "Jiujiu" in the China lunar calendar, which is used to calculate the seasons. The calculation method is to calculate winter from winter to Sunday (which means the beginning of cold). Every nine days are called 19, the first nine days are called 19, the second nine days are called 29, and so on until the ninth nine days, when the number reaches 998 1 day. At this time, winter has passed and spring has arrived.

On the third day after the summer solstice, it began to rain. As the saying goes, "A little summer heat is closely linked with a big summer heat, and it will be hot when the temperature rises." This period of time is called dog days.