How many weeks after the expiration of the deadline should I expect a response?

I applied to a few universities that have deadlines Dec 1st, Dec 15th and such. And I’m curious as to when I can get responses. The universities are UCLA, Stony Brook, USC, Penn State, NCSU.

Well, it varies by school. Usually you should hear back from them in couple of months or so. Universities usually mail out decisions in March or sometimes early february. One of the things you can do is to write to the graduate school admissions email and seek for the decision date.