How long can beginning of autumn wear long sleeves?

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 second 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. According to the calculation method of "dog days", the days of "beginning of autumn" are often in the middle of dog days, that is to say, the heat is not over, and the real coolness usually comes after the Millennium solar terms.

Astronomy: the traditional method of dividing the four seasons according to the change of astronomical phenomena. The starting point of the four seasons is "Li Si" in the 24 solar terms, so beginning of autumn is the starting point of autumn. Beginning of autumn is the starting date of autumn according to the astronomical observation position. Autumn begins in the beginning of autumn and ends in beginning of winter, which is the result of celestial movement. ?

Temperature method: At present, the four seasons are often divided according to the temperature change, which is divided by the "average weather temperature" of modern scholar Zhang Baokun. According to the weather average temperature method, the average daily temperature for five consecutive days is between 10℃ and 22℃, which is regarded as autumn.