https://www.timeanddate.com/time/am-and-pm.html

So when it is noon which is AM and which is PM?

However, most digital clocks and a majority of sources, including timeanddate.com, designate midnight as 12 am and noon as 12 pm. Although the precise moment of noon falls in neither category, the hour succeeding it, from 12:00:01 to 12:59:59, is clearly after noon (pm).

To avoid confusion when referring to the precise moment of noon or midnight, we recommend using the designations 12 noon and 12 midnight instead.