When is autumn?

Traditionally, "beginning of autumn" with 24 solar terms is the starting point of autumn. On August 7th or 8th every year, when the sun reaches longitude 135, it is the "beginning of autumn" among the 24 solar terms.

In China, traditionally, "beginning of autumn" in the 24 solar terms is taken as the starting point of autumn. Entering autumn means that rainfall and humidity tend to decrease or decrease. In nature, the qi of Yin and Yang began to change, the yang gradually declined, the yin gradually emerged, the climate changed from hot to cold, and everything was born with cold and gradually declined.

According to modern meteorology, the autumn in the north temperate zone is from August 23rd (summer) to165438+1October 22nd (light snow). Autumn in the south temperate zone is from February 19 (rain in the northern hemisphere) to May 2 1 (xiaoman in the northern hemisphere).

phenology,bioclimatology

Autumn is the harvest season, and many plants mature in autumn. In autumn, in nature, the qi of yin and yang begins to change, the yang is gradually declining, the yin is gradually flourishing, the climate turns from hot to cold, and everything is born with cold and gradually declines. This is the season of alternating hot and cold. As the temperature gradually drops, the leaves of many deciduous perennial plants will gradually change color, wither and fall off, leaving only branches for winter.

Panicum miliaceum will come to the end of his life, wither and die. Seasonal variation covers many aspects of climate characteristics, and it is not accurate to judge autumn only by temperature. The most obvious change in autumn is that the leaves of vegetation change from lush green to yellow, and the leaves begin to fall and the crops begin to mature.