In August, the wild goose gate opens, and the geese are full of frost.

In August, the wild goose gate opens, and the frost begins at the foot of the wild goose, which means that the wild goose begins to fly south in August, and once it flies south, it will frost.

From the saying Song: I threw away the autumn fan, dressed casually in February and August, with little summer rain and early autumn frost. In August, the geese come to open, and the frost is under their feet.

After beginning of autumn, the weather turned cold, so there was no need for a fan. The weather changed from cold to hot in February, from hot to cold in August, and began to change from hot to cold. Coupled with physical differences, people's clothes are naturally different. When there is little rain in summer, autumn frost comes early. In August of the lunar calendar, geese begin to move south. When geese fly by, the first frost will come.

Beginning of autumn is the solar term that begins in autumn. On August 7th or 8th every year, when the sun reaches 135 degrees, it is beginning of autumn. Twenty-four solar terms: "July Festival, set up a word to solve spring (beginning of spring). Autumn is also awkward, and this is the thing. "

Beginning of autumn generally indicates that hot summer is coming and autumn is coming. After beginning of autumn (solar term), the next rain will cool down after autumn, so there is a saying that "an autumn rain will bring a cold". Cui's Four-person Monthly Order in the Eastern Han Dynasty: "It is chilly to welcome beginning of autumn; In the autumn night, it is hot to the end. "

As early as the Zhou Dynasty, on the day of beginning of autumn, Emperor Tiandi personally led the princes and doctors of the Three Kingdoms and Nine Counties to the western suburbs to welcome autumn and hold a sacrificial ceremony. According to records, the plane tree planted in the basin was moved into the temple in the early autumn of Song Dynasty. When it arrived at beginning of autumn, the historian announced it loudly. After the play, the phoenix tree dropped one or two leaves to express autumn.