Traditionally, the starting point of the fall season is the "Liqiu" of the 24 solar terms. On August 7 or 8 every year, when the sun reaches 135° of the yellow meridian, it is the "Liqiu" of the twenty-four solar terms;

In China, the "Liqiu" of the twenty-four solar terms is traditionally used as the starting point of the autumn season. Entering the fall means that rainfall and humidity tend to decline or decrease. In nature, the yin and yang qi began to change, the yang qi gradually retreat, yin qi gradually born, the climate from hot to cold, everything with the cold growth, gradually decline.

From the modern meteorological division, the fall of the northern temperate zone in August 23 (heat) ~ November 22 (snow); the southern temperate zone in the fall on February 19 (rain in the northern hemisphere) ~ May 21 (the northern hemisphere small full).

Climacteristics

Autumn is the season of harvest and many plants mature in the fall. During the fall season, in nature, the qi of yin and yang begins to shift, yang qi gradually recedes, yin qi gradually arises, the climate changes from hot to cold, and everything grows with the cold and gradually depresses, which is the season of alternating heat and cold. As the temperature gradually drops, the leaves of many deciduous perennial plants will gradually change color, wither and fall, leaving only the branches to survive the winter.

Annual herbs will reach the end of their lives, withering and dying. The change of seasons encompasses a wide range of climatic features, and it would be inaccurate to use temperature alone as a criterion for determining the onset of fall. The most noticeable changes in the fall are that the leaves of the grasses and trees turn from lush green to yellow and begin to fall, and the crops begin to ripen.