Interesting, is midnight the end or beginning of the day?
12:00 AM implies it is the beginning since AM is in the morning.
We toast New Years on Dec 31st at Midnight, the end of the day.
Here is a WIKI defn:
Midnight marks the beginning and ending of each day in civil time throughout the world. It is the dividing point between one day and another. With
12-hour time notation, authorities recommend avoiding confusion between noon and midnight by using "midnight", "12 midnight", "12 mi", or "12:00 midnight."
[1]In the United States and Canada, digital clocks and computers commonly display 12
a.m. right at midnight. While that phrase may be used practically, it helps to understand that any particular time is actually an instant. The "a.m." shown on clock displays refers to the 12-hour period following the instant of midnight, not to the instant itself, because at that time, you are looking at clocks midnight has already passed and the period before noon (a.m.) of a new day has begun. In other words, 11:59
p.m. shows until midnight; at the instant of midnight, it changes to 12:00. Simultaneously, the p.m. changes to a.m., though, strictly speaking, a.m. does not apply to the instant of midnight which separates p.m. and a.m. In
24-hour time notation, "0:00" and "0:00:00" refer to midnight at the start of a given date. Some styles, such as
ISO 8601, allow 24:00 to refer to the end of a day. Noon is 12:00:00.