Although the ancestors in ancient times did not have developed high-tech technology to calculate time and predict the weather, they summarized the experiences they discovered in long-term agricultural labor and revealed the laws of climate change to people. , and summarized it into short proverbs and poems to facilitate daily use and dissemination.
Cold in thirty-nine and hot in three volts
The climate changes of a year are integrated into short poems, and the sentence "three volts in the summer solstice" is people's response to climate change. To summarize, it means that the Summer Solstice solar term has arrived, but it is not yet the hottest time of the year. The third "Gength Day" after the Summer Solstice solar term begins to fall, and this time is the hottest time of the year. As the saying goes This is the truth behind the saying "cold in the 39's and hot in the 3 volts". After the summer solstice, the number of daylight hours in the Northern Hemisphere gradually decreases. At the same time, after the summer solstice arrives, the night sky gradually changes into a summer starry sky.
Ten days are one Geng
If you want to understand the so-called three Geng in this sentence, you must first understand what Geng is. One Geng is specifically ten days. "Three Geng" is what the ancients said The "Third Geng Day" mentioned in the Heavenly Stems and Earthly Branches chronology was recorded by the ancients by combining the 10 Heavenly Stems and the 12 Earthly Branches. Among them, the word "G" in "Three Gengs" is the number "A," in the Heavenly Stems. "Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui" is the seventh character among the 10 Heavenly Stems. Geng day is repeated every 10 days.
The time of Zhongfu is not fixed
The specific number of days in Zhongfu needs to be calculated based on the time of the zodiac signs. In fact, counting from the summer solstice, the third celestial stem The day marked as "Geng" is called Chufu (also called Toufu), the fourth Geng day after 10 days is called Zhongfu (also called Erfu), and the first Geng day after the beginning of autumn is called Mofu (also called Sanfu). , generally called "Three Volts". The first and last days are fixed for 10 days; the time for the middle day is not fixed, some years are 10 days, some years are 20 days, mainly from the summer solstice to the beginning of autumn, there are several days in a day. Decision: If there are four Geng days, the interval between the middle and last days will be 10 days, and if there are five Geng days, the interval will be 20 days.