Sept furnaces are fine....unless they are truly historic, they usually lack a big punch like we see earlier in the summer. The really big stuff usually only ends up as like one day of 90+....unless maybe you are on the tarmac at BDL.
I want it above average until maybe mid november. I'll embrace a couple cold shots to remind us the season is changing, but for the most part, give me like 80/55 in Sept and 70/45 in October.