It’s always a good time to write, but how do you write time?
As with just about everything in writing, it depends. According to the Chicago Manual of Style, the guide most creative writers follow, if you plan to use the words o’clock, then write out the time rather than use a numeral. Use o’clock only when the time is a whole number.
I plan to leave for school at eight o’clock.
If you’re writing time in even, half, or quarter hours, you can use words as well, but don’t include o’clock.
I plan to leave for school at a quarter after eight.
Use numerals to write time when noting minutes as well as hours.
I plan to leave for school at 8:20.
In the sentence above we don’t know if the person is leaving in the morning or the evening. For those designations, we use abbreviations for ante meridiem and post meridiem. The first twelve hours of the day are identified by a.m. and the second twelve hours, by p.m.
I plan to leave for school at 8:15 p.m.
I see people write these abbreviations in a host of different ways—lowercase letters without periods (am), lowercase letters with periods (a.m.), capital letters without periods (PM), capital letters with periods (P.M.), small caps without periods (am), small caps with periods (a.m.).
Chicago Manual of Style recommends using lowercase letters with periods with a space after the numeral, so that’s the rule I follow.
Is there one right way to designate morning or afternoon times? No, not really, but as with most style issues, consistency is key. If you write am using lowercase letters and no periods, do that throughout your entire piece. Don’t vary your style.
When writing about an event that occurred at 12:00 a.m. or 12:00 p.m., it might be better to use midnight or noon. Less confusion that way.
Now that you know how to write time, it’s time to write!