Midnight and Noon: AM or PM? Which Abbreviation Is Correct? Ante meridiem is commonly denoted as AM, am, a.m., or A.M.; post meridiem is usually abbreviated PM, pm, p.m., or P.M. Like many other sources, timeanddate.com uses “am” and “pm” when using the 12-hour format, but the other variants are equally correct and widely used. The main ...

I used to think PM/AM was correct, but at some point, I switched to using p.m./a.m. for reasons I can't recall. I know that in practical, casual writing, people tend to use whatever form is most convenient to them, but I'm curious about what the official usage—should it exist—actually is.

大多数数字时钟和大多数来源，将午夜定为12 am，中午定为12 pm。虽然正午的准确时间不属于这两类，但它之后的时间，从12:00:01到12:59:59，显然是正午以后。为了避免混淆，当提到中午或午夜时，我们建议使用12 noon和12 midnight 。

Time Zone Converter – Time Difference Calculator. Provides time zone conversions taking into account Daylight Saving Time (DST), local time zone and accepts present, past, or future dates.

7:11 am – 7:37 am 7:07 pm – 7:33 pm. Previous Moon Phase. New Moon March 29, 2025 9:57 pm. Next Moon ...

12 小时制将一天中的 24 小时分为两个时段，每个时段持续 12 小时。第一个时间段指定为上午，标记为am，它从午夜运行到中午。第二个时段，标记为 pm，涵盖从中午到午夜的 12 个小时。 AM = Ante meridiem : 中午之前. PM = Post meridiem : 中午之后

United States time now. USA time zones and time zone map with current time in each state.

2018年5月25日 · From a user interface perspective, a "Period" label is too ambiguous, and "Meridiem Indicator" too pedantic, still leaving "AM/PM" as the best choice. Aside. As for the actual meanings of AM/PM, they come from the Latin "ante meridiem" ("before noon") and "post meridiem" ("after noon").

2015年6月10日 · I believe the use of AM and PM increased during the early days of computer systems. Back in character-mode days, one had to be especially parsimonious with screen and page "real-estate". Uppercase AM and PM without punctuation used only two characters, and there was also no space between the time value and the AM or PM value.

6:27 am – 6:53 am 7:32 pm – 7:58 pm. Previous Moon Phase. New Moon March 29, 2025 3:57 am. Next Moon ...