After what solar term, it gets cold.

Beginning of autumn is the13rd solar term among the 24 solar terms, and it is celebrated from August 7th to 9th in the Gregorian calendar every year. At this time, the bucket handle of the Big Dipper points southwest, and the sun reaches longitude 135. Beginning of autumn is the first solar term and the starting point of autumn. Autumn begins in the beginning of autumn and ends in beginning of winter, which is the result of celestial movement.

Beginning of autumn doesn't mean the extreme hot weather is over. Beginning of autumn is still in the summer heat period, and the summer heat will not come out until the third solar term in autumn. It's still very hot in early autumn. The so-called "heat is in the dog days" is also called "beginning of autumn drops later", and there is at least "falling" hot weather after beginning of autumn. "Three Volts" can be divided into initial volt, intermediate volt and final volt, and its date is determined by the matching of solar term date and main branch year date.

Autumn is a season of alternating hot and cold. "Guanzi" said: "Autumn begins in the shade, so everything is harvested." After entering autumn, the climate changed from rainy and humid in summer to dry and rainy in autumn. In nature, the qi of yin and yang begins to change, the yang gradually closes, the yin gradually grows, and everything declines with the sinking of the yang.