Is noon 12 am or 12 pm?

To avoid confusion, the correct way to express 12 o'clock is 12 noon or 12 midnight.

Alternatively, the 24-hour clock system may be used - 12:00 and 24:00 (or 00:00) respectively.

The abbreviation am stands for ante-meridiem (before the Sun has crossed the meridian line) and pm stands for post-meridiem (after the Sun has crossed the meridian line).

At 12 noon, the Sun is at its highest point in the sky and directly over the meridian. It is therefore  neither 'ante' (am) nor 'post' (pm).

Ever wondered why there's 12 months in a year, seven days in a week or 60 minutes in an hour?

Explore more questions about time 

What is Greenwich Mean Time (GMT)?

Why is Greenwich known as 'the home of time'?

Which years have leap years - and can you have leap seconds?

How is time measured?

The Royal Observatory is open daily from 10am

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