Alternatively, you could use the hour clock system, where is noon and or is midnight. At exactly 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 meridiem. At 12 midnight it also neither am nor pm.
If all these questions about time have got you in a spin, why not visit the Royal Observatory , where many more mysteries of time await Which years are leap years and can you have leap seconds? Because the Earth takes a little over days to orbit the Sun, we need to make adjustments to keep the seasons from drifting: leap years and even leap seconds.
How do we divide time? While days and years are fairly neat astronomical events, what explains months, weeks, hours and minutes? Why do we have daylight saving? When do the clocks go forward in ? Marking the start of British Summer Time, the clocks 'spring forward' in March, meaning we'll lose an hour's sleep When do the clocks go back in ? Therefore, it is always better to refer to 12PM as noon and 12AM as midnight respectively even if analog and digital clocks do label them as the former.
What is DST? Current Time In. Wake Island U. The most common argument in favor of using the hour convention is easy pronunciation. It is easier to say 6 PM rather than 18 hours. Hence, the use of AM and PM is more of a convenience decision. Another confusing notion about the use of AM and PM is to understand how to properly write it. Different style guides suggest different types of writing the abbreviation. Also, the use of the period between the letters A. The lack of consistent rules among all style guides is the primary factor why people could face the issue of how to write the time appropriately.
For the people who just encountered the hour convention, it might be difficult to memorize to what part of the day AM and PM refer to. AM — starts with the first letter of the alphabetA. Considering that AM corresponds to the start of the day, knowing that A signifies the start of the alphabet could be a perfect point of reference for memorizing.
Meanwhile, the fact that AM is alphabetically closer that PM should be the designation that it is before the midday.
With the ambiguity of hour clock convention, many establishments require that this time representation should be scrapped altogether. It could be used in conversations and informal communication only. However, the legal documents, schedules, and other interactions that require high precision time identification should follow the hour format to avoid confusion with the denomination of noon and midnight. Considering that hour clock is the most effective system of timekeeping and it is used for high precision coordination, the international organizations managed to provide the most effective solution.
Therefore, the standard ISO implies that all countries should use the specific format to indicate date and time hour clock and it should be used for documentation and formal communication 2.
However, the international agreements do not directly regulate how organizations within the countries use timekeeping format for the interactions and communication. Hence, some domestic organizations could proceed to use AM and PM. The most strange scenario remains to be the moment when one watches on the hour clocks or wristwatches and should convert the time into the hour format.
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