Hours where any events are running (these have been the same for the last few years):
Saturday: 8:00am to 2:00am
Sunday: 8:00am to 2:00am
Monday: 8:00am to 5:00pm
At some point Kumoricon may become a 24-hour con but nothing has been changed from these hours yet.
Staff hours depend entirely on your position. Some positions have shifts (either during attendee hours, or during setup or teardown the day before or after), and others have you responsible for a certain area which may mean you could be called at any time to need to do something. A very few positions may even have you doing something during night hours when no attendee events are running. Such a position may or may not also have specific shifts. Some staff positions require responsibility for something outside the convention.