"What is the True Meteorological Date ... ???" At the time & now I am guessing you were asking when fall officially began. If that is correct I posted information regarding the first day of fall.
Bobbi if you are interested in a little more reading. Here are the other three times of the year that denote the beginning of each season. I found the December & June had more information about the other seasons etc... (I just glanced over the articles) The seasons change every three months; the days of the change can be the 20 or the 21 or the 22. Each season & year is different.