Hello gist,
There's no real "better" month to interview. People say it may be better to interview later in the process because most of the selection committees will still have you fresh in their mind. Each program has their own logistics. I got into the place I ranked number 1... and I interviewed here in mid december. Bottom line, it doesn't really matter.
My other suggestion would be to NOT try and schedule too many interviews in the same week. It can become extremely draining, and all those hospitals start to look the same (not a good thing if your trying to remember specifics of each program).
Good luck on your upcoming interview process.
Nardo