How did the ancients record the phenology of the solar term beginning of autumn?

The ancients used this sentence to record the phenological phenomena of solar terms in beginning of autumn: cool wind coming, dew falling and cicada singing. Beginning of autumn is the first 13 of the 24 solar terms and the first solar term in autumn, marking the official start of the Qiu Meng season.

In early autumn, Beidou points southwest. From this day on, autumn began, the autumn was crisp, the moon was bright and the wind was clear. Since then, the temperature has gradually decreased from the hottest time.

The day when it was handed over to beginning of autumn was July of the lunar calendar, which was also called "Shen Yue Day". In beginning of autumn, the sun is at declination+16 19', which is more southerly than +23 26' from summer to sun.

Beginning of autumn has arrived, but not in autumn. The division of climatic seasons should be based on the "average climate temperature", that is, the local average temperature is below 22℃ for five consecutive days, which is the real autumn.

The earliest areas of Qiu Lai, Heilongjiang and northern Xinjiang will also fall in mid-August, so the daytime in Beijing will be shortened to 14 hours and 04 minutes (summer solstice is 15 hours).