Gives you an idea of how ridiculous the pattern would have to be to squeeze out a T in September. It’s really not plausible (but again, it’s happened once in Pittsburgh).
As for records, verbatim that gives us a high of about 43 at PIT on 9/29. We have 5 September days in our records with highs in the 40s, none since 1950, and none with a high below 46. MDT has done it once: a high of 48 on 9/28/1984.