Dates and Times
Use figures for days of the month. Omit the ordinal designations of nd, rd, st, th.
Place a comma between the month and the year when the day is mentioned:
- On April 27, 2009, Communiversity brought together hundreds of people.
Do not place a comma between the month and the year when the day is not mentioned:
- In April 2009, Communiversity brought together hundreds of people.
When a month is used with a specific date, abbreviate the month according to AP style: Jan., Feb., Aug. Sept., Oct., Nov. and Dec. (all others spelled out). Spell out when using alone or with a year alone:
- Aug. 27, 2011
- August
- August 2011
Use figures for years without commas: 2011.
Use the year, a hyphen and the last two digits to refer to a period of time within the same century as an adjective, but full years joined by a hyphen when the range crosses into another century:
- the 2011-12 academic year
- the 1999-2000 academic year
Use “to” instead of a hyphen when the year or time is a noun:
- from 1989 to 2005
- The meetings will take place from 8 to 11 a.m. Monday through Friday.
When abbreviating years to two digits, put an apostrophe in front of the years:
- the Class of ‘76
- the summer of ‘69
Dates following a day of the week should be set apart by commas:
- He decided that Friday, Oct. 12, would be a convenient date.
Times generally come before days and dates:
- The performance will take place at 3 p.m. Friday, Oct. 12.
When emphasizing the exact time, or when using a.m. or p.m., use figures (omitting 00 for on the hour):
- 7 p.m.; 7:30 p.m.
12 a.m. should be referred to as midnight; 12 p.m. should be referred to as noon.
Hyphens may be used with dates, and should always be used with dates when both days of the week and dates are included.
- The workshop is set for Monday through Thursday, July 18-21.
Exception:
The Office of Public Relations recognizes that some publications, such as posters and invitations, call for a design treatment that demands the more elegant presentation offered by Chicago style (such as spelling out a month).
Centuries and Decades
- Noun: the 20th century
- Adjective: 20th-century literature
- the 1980s
- ‘80s fashion
