How to calculate the first Geng Day? How to calculate the first Geng Day?

1, how to calculate the first Geng day: the summer solstice is a three-boxer, and the boxer is a boxer. After summer, the third day was boxer, and it began to fall, that is, the first autumn.

2. The number of heavenly stems is 10, which is A, B, C, D, E, Ji, G, Xin, Ren and Gui, and the number of earthly branches is 12, which is Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen and You. Heavenly stems and earthly branches, Jia Zi, Yi Chou, Bing Yin, Ding Mao. Cross match 60 times, so it's called 60 flowers. "Three Geng" means meeting three "Geng" characters, and the third Geng Day will be the first time. Because the number of heavenly stems is 10, there is a Geng Day every 10 day, such as Geng Zi Day, Geng Yin Day and Chen Geng Day. 365 days a year (366 days in leap year) is not an integer multiple of 10. One day this year is Geng Day, and next year is not necessarily Geng Day. Due to the uncertainty of Geng day, the date of accommodation is different every year. The dog days are the hottest time of the year, which can be divided into three days: the first, the middle and the last. This is because after the summer solstice, the nights are short and the days are long, and the sunshine is close to direct. But the summer solstice is not the hottest time, because at this time, a large part of the heat absorbed by the ground radiates at night. But it absorbs more heat and dissipates less heat every day, and it gets hotter every day. It will be the hottest in about 20 days to three volts.

3. Three volts are divided into: initial volt, intermediate volt and final volt. The third Geng Day after long summer is the first day of first lodging, the fourth Geng Day is the first day of middle lodging, and the first Geng Day after beginning of autumn is the first day of last lodging. The first day and the last day are 10, and the days in between are not fixed. There are four Geng days between the summer solstice and beginning of autumn, with 10 in the middle and five Geng days with 20 days in the middle. V means summer. Since the summer solstice, the days are short and the nights are long, and there is a cold factor lurking in the middle of the heat. People often use "dog days" to describe the climate characteristics in midsummer. This statement has a long history in our country. As early as the Qin Dynasty, the hottest time of the year was called dog days.