What are maple leaves in autumn?

In autumn, maple leaves are as red as burning flames.

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).

At present, the division of the four seasons in China is often based on the change of temperature, and the division of "climate average temperature" by modern scholar Zhang Baokun is adopted. According to the weather average temperature method, there are two main criteria to judge autumn. First, the average daily temperature for five consecutive days 10℃-22℃ can be regarded as autumn and become a "short mark"; Second, the moving average temperature of five consecutive groups is lower than 22℃. A set of moving average temperatures refers to the average temperature of the day plus the average temperature of the previous four days divided by 5 to get the moving average temperature of five days, which is a "sliding scale". Entering autumn means that the hot weather has passed and it is beginning to cool down.