The history of long summer is very short. What is the history of the long summer?

1 Origin of the Long Summer: The Long Summer solar term was established at the end of the Warring States Period (239 BC), indicating the change of seasons, and all seasons are the days of long summer.

2. According to the standard of climatology, the average temperature in long summer in the first five days reached 22℃. In the middle and lower reaches of the Yellow River, the waiting temperature in the long summer season is close to the climatological standard, which is the origin of the twenty-four solar terms. From this point of view, it is practical to regard the Long Summer Festival as long summer in the 24 solar terms.