When did the dog days begin? What does it mean?

The dog days appear in light summer heat and heavy summer heat, and are the hottest, humid and sultry day of the year, from early July to mid-August in the solar calendar every year. The "crouching" in "dog days" refers to "crouching evil", which is the so-called "six evils" in summer evil. Three or nine days refers to the third "nine days" from the winter solstice, that is, 19-27 days after the winter solstice, which is the coldest time people feel.

The so-called "dog days" refers to the "dog days" of the lunar calendar, which is the hottest period of the year. It can be understood as "squatting" means that the weather is too hot to move. The dog days are the hottest thirty or forty days in a year in the Central Plains. From summer to the third Geng day in the future, the first day is 10, the middle is 10 or 20 days, and the last day is 10.

China lunar calendar uses "99" to calculate seasons. The first day of the winter solstice is "19 days", and every 9 days is a "9". The first nine days are called "19", the last nine days are called "29" and so on. "99" 81days later, winter ends and spring enters, and the coldest period of the year is.

Xuchang, Henan Province (the capital of the Three Kingdoms) has a thousand-year proverb: "If you don't make a move in 1929, you will walk on the ice in 3949, watch the willows cross the river in 5969, wash your hands and cross the river in 7989, and the old man will stand on the wall in 9981, not afraid of cold, but afraid of hunger."