I submitted June 1st and didn't get my first interview until August 31st, next came in September, one in both December and January but three were really late (March-ish) when I had been complete at those schools for months. Better late than never 🙂
SDN makes you very neurotic about timing, remember this population isn't necessarily representative of the applicant pool (in my class of 19, I am the only person who applied before August).
Good Luck!!