We take:
September around here used to be more of a transitional month into fall. It often would start on a warm note, but then turn fairly cool. Increasingly, the month is more like a fourth month of summer with many days well into the 70s and 80s. The nights are also a lot warmer than 30 or 40 years ago.
Since 1872, if you look at the top 20 Septembers you will find 10 of them in the past two decades.
https://www.bostonglobe.com/2020/09/07/metro/keep-your-ac-unit-out-summer-isnt-over-yet/