In a quandary about how to abbreviate days of the week and months? Welcome to the twenty-first century! Let’s take three excellent style guides and see what they offer.
THE GREGG REFERENCE MANUAL, NINTH EDITION says, “Do not abbreviate days of the week and months of the year except in tables or lists where space is limited.”
Gregg is addressing business documents, for the most part. It suggests that abbreviations are appropriate when the emphasis is on “communicating data in the briefest form. In other kinds of writing, where a more formal style is appropriate, use abbreviations sparingly. When in doubt, spell it out.”
The latest AP STYLEBOOK says, “When a month is used with a specific date, abbreviate only Jan., Feb., Aug., Sept., Oct., Nov. and Dec. Spell out when using alone, or with a year alone.”
It says that in tabular material, use three-letter forms without a period (the first three letters of each month).
The stylebook, published primarily for journalists, also says to capitalize the days of the week, and to not abbreviate them except when needed to facilitate tabular composition.
THE CHICAGO MANUAL OF STYLE, 15th Edition, targets authors, editors, proofreaders, indexers, copywriters, designers, and publishers. “Where space restrictions require that the names of months be abbreviated,” it says, “one of the following systems may be used. The second and third, which take no periods, are used respectively in computer systems and indexes of periodical literature.” It follows with these examples:
- Jan. (or Jan or Ja)
- Feb. (or Feb or F)
- Mar. (or Mar or Mr)
- Apr. (or Apr or Ap)
- May (or May or My)
- June (or Jun or Je)
- July (or Jul or Jl)
- Aug. (or Aug or Ag)
- Sept. (or Sep or S)
- Oct. (or Oct or O)
- Nov. (or Nov or N)
- Dec. (or Dec or D)
CMS says much the same about days of the week. Use where space restrictions exist as follows:
- Sun. or Su
- Mon. or M
- Tues. or Tu
- Wed. or W
- Thurs. or Th
- Fri. or F
- Sat. or Sa