The time of day that determines when the scheduling Posted Day begins. This primarily affects how the staffing needs are loaded, but may also affect how the coverage is totaled.
This allows for a Coverage Day to be different than a normal calendar day, which is midnight to the following midnight. In many cases the coverage day is offset, such as 7:00 am one day to 7:00 am of the following day, which may cause one or more coverage periods to exist entirely outside of the assigned calendar day. For example, the N2 coverage period of 11/11 may actually be 3:00 am - 7:00 am on the morning of 11/12.