Does autumn begin in beginning of autumn?

Beginning of autumn is a solar term that begins in autumn, which indicates that hot summer is coming and autumn is coming, but it is not the same as entering autumn.

Autumn is defined according to the standard of dividing four seasons in climatology. Only when the average daily temperature is stable below 22℃ for five consecutive days can it be considered as autumn. Moreover, the climatic conditions are different every year, and there is a big difference between morning and evening, and the time difference can reach two or three weeks.