Here in Nebraska, our season starts Sept 15, and buck hunting is always good for the first two weeks, then tapers off until late Oct.
I believe some of it has to do with food sources maturing, and changing, as well as pressure. My personal favorite for this time of the year is an alfalfa field that has had 4 cuttings and is coming back. If the deer aren’t pressured and the field is isolated from casual observers etc. If you play the wind, and keep disturbance and residual scent down you should keep seeing your deer for a while.