This is fascinating. For team BA, the month by month splits are April .238, May .236, June .246, July .257, August .237, September .271. For runs scored it's 39, 52, 51, 35, 38, 39. They have hit far better in September than any other month, but haven't scored more runs. HR probably explains a lot of that: 29, 39, 45, 30, 36, 30.
Pitching is where it really jumps around. April ERA, 3.04. May jumps to 4.03, June 3.34, July 3.52, August 2.61--and I don't remember August being that spectacular, September 4.96. 4.96. Pitching in September has just nose-dived. Diven. Doved.