Calendar solar terms are wrong

Let me tell you clearly: No.7 is beginning of autumn. We have a custom here that beginning of autumn eats watermelons. It was yesterday that the older generation should have some algorithms, which should be based on that old almanac. Gregorian calendar: at 23: 57 on August 7, this is defined according to the science of the earth's revolution. The above situation may be because it was not handled well at this time.

Hope to adopt