After reading the explanation below, it is now easier to remember which is which. Keeping in mind the meaning of am and pm helps.
Now I basically reason like this: I easily remember 1:00 pm is 1 hour after noon. The 59 minutes before that are after noon as well. Since the majority of time from 12:00 to 1:00 pm is after noon (pm), assign pm to this 12:00.
Here is more detailed information.
- The abbreviations am and pm derive from Latin:
- AM = Ante meridiem: Before noon
- PM = Post meridiem: After noon
- Midnight and Noon: AM or PM?
- The main weakness of the 12-hour system is a widespread confusion about which abbreviation should be used for noon and midnight: neither moment can logically be identified as before noon (am) or after noon (pm). For example, the moment of midnight occurs precisely 12 hours after noon on the previous day and 12 hours before noon on the following day.However, most digital clocks and most 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.
- Midnight Confusion
- Another source of confusion is the lack of a date designator in the 12-hour system, making it impossible to logically identify a correct moment in time when only a date and 12:00 am (midnight) is provided.Imagine being asked to pick up a friend at the airport at 12:00 am on April 13. Would you go there at midnight between April 12 and April 13? Or 24 hours later?One way to overcome this problem is to sacrifice accuracy for clarity. Your friend could ask you to be at the airport at 12:01 am on April 13 or, if the following midnight is meant, at 11:59 pm on April 13. Alternatively, the 24-hour format could be used. Here, 0:00 refers to midnight at the beginning of the day while 24:00 is midnight at the end of the day.