time of day; span of time

If a time of day falls exactly on the hour, don’t style it with a colon or zeroes; just give the hour and “a.m.” or “p.m.” For other times of day, use the colon and numerals as needed.

Examples: 6 a.m.; 6:30 p.m.; 8:40 a.m.; 9 p.m.; 9:01 p.m.

To represent a span of time:

• Give the beginning and ending times separated by a hyphen, with no spaces on either side.
• If both the beginning and ending times are in the morning or in the afternoon, only use “a.m.” or “p.m.” once, after the ending time.
• If the beginning and ending times are in different parts of the day, use “a.m.” and “p.m.” after each time as needed.

Examples:

• The lecture takes place 9-11 a.m.
• The festival will be held 10 a.m.-2 p.m. in the courtyard.