While fall started on September 1 for meteorologists and climatologists, today is the first day of astronomical fall.  Most of the Southeast will be feeling summer-like temperatures for a few more days before cooler air moves into the region in about a week.  You can read more about why climatologists and astronomers have different definitions of fall from NCEI at https://www.ncei.noaa.gov/news/meteorological-versus-astronomical-seasons and read more about the autumnal equinox at EarthSky at https://earthsky.org/earth/sun-earth-equinox-explanation-illustrations-ottewell?mc_cid=12c2531300&mc_eid=b22da16cce.

Source: Steve Jurvetson, Commons Wikimedia