

The same is true for midnight, but there is an added issue of which day midnight refers to (see below). as soon as it the 12:00 appears, and not delay the display of the p.m.

For example, it would be applicable for a digital clock changing from 11:59:59 a.m. It is fair to say, however, that the shortest measurable duration after noon should be designated as p.m. Also, midnight is both twelve hours before noon and twelve hours after noon. Since noon is neither before noon nor after noon, a designation of either a.m.

To illustrate this, consider that "a.m." and "p.m." are abbreviations for "ante meridiem" and "post meridiem," which mean "before noon" and "after noon," respectively. This is a tricky question because 12 a.m.
