I was looking at old emails from last year and Dartmouth was the only one of my sites that let me know (rejection) before December 1st. I got 3 interview offers last year, all about a week into December. Based on this thread, 2 other sites that I applied to have already offered interviews this year (but no rejections yet), with one of them offering interviews well before its recent deadline. So, I'm not worried yet but I'm very impatient.
On the other hand, sites that have quick turnaround times (<5 days after the deadline) are almost certainly just sorting by stats, like hours, publications, etc., and not considering the "meat" of the application (cover letters, essays, etc.). That bugs me. (At least that's my theory of how hundreds of apps can be processed in a few days.) It also bugs me to get the exact same rejection email 2 years in a row. The first time, I thought they meant it. This time, I see it's just easy to send and makes it easier for applicants to hear/accept.
So hard to wait!😴