How to calculate the ambush of Xia in the middle of the night

According to the yearbook, "summer to sunset is on the third Geng day", which means "countdown from summer to Sunday" and then fall asleep on the third Geng day.

The "Geng Day" here refers to the days prefixed with "Geng" in the ancient "Ganzhi Jiri Law". The almanac also stipulates that the first "Geng Day" after the solar term "beginning of autumn" is the day when the last volt begins.

The "dog days" are determined according to the "laws of solar terms" in ancient China. Every summer to the future, the third Geng Day (referring to the day when the word "Geng" appears in the main branch year) is the first Geng Day, the fourth Geng Day is the middle one, and the first Geng Day after beginning of autumn is the last one. Together, it is called the third volt.

As the saying goes, "It's hot in dog days." According to our traditional calendar, today we entered the hottest dog days in summer.

Three volts refers to three consecutive periods: the first, the second and the last. The third Geng Day after long summer is the beginning of the first summer, the fourth Geng Day is the beginning of the middle summer, and the first Geng Day after beginning of autumn is the beginning of the last summer, which lasts 10 day, but in some years, the middle summer lasts for 20 days, such as this year.

Generally speaking, the average temperature is the highest in dog days.