Dating

 You know what drives me crazy? Signs that say "closing at 12 PM" what time is that?????

According to Royal Museums Greenwich:

'Noon' means 'midday' or 12 o’clock during the day. ‘Midnight’ refers to 12 o’clock during the night. Simple right?

Well, maybe not, especially if you're using a 12-hour clock.

When most people say 12pm, typically they're talking about the middle of the day: 12 noon. When they say 12am, they normally mean 12 midnight.

While some people follow this convention, technically it's not quite right – as you'll see from the definition of am and pm below. To avoid any confusion (and to make sure you arrive on time), it might be best to say 12 noon or 12 midnight instead.

Alternatively, you could use the 24-hour clock system, where 12:00 is noon and 00:00 (or 24:00) is midnight.

Once every month, the correct and the US date formats agree.