General Application Due Date Question

When a school says that their application is due 1/4/2012, does this mean I need to have it in my 11:59 pm on 1/3/2012 (i.e. before the listed due date)? Or do I need to make sure it is submitted at some point on 1/4/2012?

If it's different for every school, does anybody have an idea where to find this information? Many schools are closed this week for the holidays, and I'm sure they will be lambasted with calls early next week.

Thanks!