Best recommendation: be available in Dec. and Jan. If you are an attractive candidate (ie. good letters, Step I > 235 or Step II > 240), you will be able to schedule when you are available.
Next best recommendation: have a smartphone or check your e-mail very frequently. Programs seem to usually schedule interviews on a first-responder basis, so there is an advantage to seeing an invite soon after it is released. Also, when mass mails are sent through ERAS, there can be a weird delay. I had one program where it always appeared to have been sent by the program about 6 - 8 hours before it was distributed by ERAS. So, check your mail on Sat. mornings too!
I applied late (CAF done Oct. 5, letters complete late Oct.), which I do not recommend. When I was offered an interview, the date selection was narrow and sometimes with very short turn-around times. If you have an application that will be attractive to programs and you apply by September 15, then you will likely be able to schedule around your rotation commitments in Nov - Jan. If you apply late like me (and have mediocre numbers like me), then your options will be curtailed. I was able to do 7 interviews in Jan. and 1 in early Feb., but I had to make extra overtures to do about 50% of my interviews. That said, most programs seem to have dates in Nov., Dec. and Jan. Nov. and Dec. seem to be the heaviest months. That said, January is a weird month--many programs seem to have 2 - 4 dates then--but this is also a month with cancellations and a motivated applicant can get in if he/she makes calls and is available at the right times. It depends on your application and your "hustle." I had good success with calling and/or e-mailing programs with specific reasons for interest. This worked better with more prestigious programs, for whatever reason. I was denied, sometimes rudely, by some less well-respected programs with this strategy.
