When is 1pm

See here. Midnight has another problem: there is nothing to tell us "is this the beginning or ending of the day". Imagine your friends say they are leaving for holiday at "midnight" on 12th March, what day should you arrive to say goodbye? Do you get there on the 11th assuming they leave at the very start of the 12th , or the 12th assuming they leave at the end of the 12th?

So, when you see something like "offer ends midnight October 15th" tell them to use one minute before or after so there is no confusion! The official according to an American, Australian and British dictionary , and most common, spelling for AM is "ante meridiem " which is a Latin phrase. Some countries, including the US, Canada, and Australia, use the hour clock format including am and pm.

What do these abbreviations mean? Is midnight am or pm? The hour system divides the 24 hours of a day into two periods lasting 12 hours each. The first hour period is designated as am. It runs from midnight to noon. The second period, marked pm, covers the 12 hours from noon to midnight.

Using numbers from 1 to 12, followed by am or pm, the hour clock system identifies all 24 hours of the day. For example, 5 am is early in the morning, and 5 pm is late in the afternoon; 1 am is one hour after midnight, while 11 pm is one hour before midnight. Ante meridiem is commonly denoted as AM, am, a. Like many other sources, timeanddate. The main weakness of the 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. Although the precise moment of noon falls in neither category, the hour succeeding it, from to , is clearly after noon.

To avoid any confusion when referring to the precise moment of noon or midnight, we recommend using the designations 12 noon and 12 midnight instead. Another source of confusion is the lack of a date designator in the hour system, making it impossible to logically identify a correct moment in time when only a date and am midnight is provided.