Using full-date (day-month-year and month-day-year) styles in running text is subject to a publisher’s preferred house style. Both day-month-year and month-day-year formats are commonly used and equally valid, even if one may make more intuitive sense than the other. However, regardless of the format being used, there are some punctuation and style standards to keep in mind. As usual, references and extra information are at the end.
Day-Month-Year Style
Several European publishers and international organizations such as UNESCO prefer the day-month-year format. Punctuation for this format is easy since it requires none (New Hart’s Rules 2014, 197; MLA 2021, 2.13; UNESCO 2004, 32).
World War II started on 1 September 1939 when Germany invaded Poland.
Month-Day-Year Style
Common with American English is the month-day-year format. Using this format requires placing a comma between the day and year, and if the year appears in the middle of a sentence, then a comma should follow the year as well (Chicago 2024, 6.41; MLA 2021, 2.13, 2.138).
World War II started on September 1, 1939, when Germany invaded Poland.
As a personal note, the month-day-year format seems a bit odd to me, but US publishers prefer it; know your publisher, and adapt accordingly.
Days of the Week
Including the day of the week requires placing a comma after it, regardless of the format being used. With the month-day-year format, if the year appears in the middle of a sentence, then a comma should follow the year as well (Chicago 2024, 6.41; New Hart’s Rules 2014, 197; UNESCO 2004, 32).
The meeting will be held on Wednesday, 4 November 2026.
The meeting will be held on Wednesday, November 4, 2026, in the main hall.
Spanning Dates
One of the most common oversights with displaying dates in running text comes from indicating a span of time. In general, two-day periods should be connected with on and and and longer periods with from and to (Chicago 2024, 6.83; UNESCO 2004, 32).
The meeting will be held on 4 and 5 November.
The meeting will be held on November 4 and 5.
The meeting will be held from 4 to 8 November. (NOT “from 4–8 November”)
The meeting will be held from November 4 to 8. (NOT “from November 4–8”)
The same standards apply when a span of time runs into the next month or year. Also notice that the month-day-year format still requires a comma after the year (Chicago 2024, 6.41).
The conference will run from 30 November to 2 December.
The office will be closed from 24 December 2026 to 2 January 2027.
The office will be closed from December 24, 2026, to January 2, 2027.
Months or Seasons with Years
Writing months or seasons with years requires no punctuation (Chicago 2024, 6.41; MLA 2021, 2.13; New Hart’s Rules 2014, 197).
We will visit in April 2027. (NOT “April, 2027”)
We will visit in spring 2027. (NOT “spring, 2027”) Note: Seasons are not capitalized (UNESCO 2004, 22).
Also keep in mind that seasons are reversed in the Southern Hemisphere, so UNESCO discourages using them to specify dates (UNESCO 2004, 22)—for an international audience, “early 2027” works better than “spring 2027.”
Decades
Decades can be written as either words or numerals (Chicago 2024, 9.35; MLA 2021, 2.138; New Hart’s Rules 2014, 198).
in the 1980s, in the eighties, in the ’80s
Important things to note: Consult your publisher’s preferred style guide. Some publishers may not accept the format “in the ’80s” (New Hart’s Rules 2014, 198). Also notice that there is no apostrophe before s (Chicago 2024, 9.35).
Ordinals
Style manuals universally discourage the use of ordinal numbers with written dates—do not add st, nd, rd, or th to dates, even if the dates may be pronounced that way when speaking (Chicago 2024, 9.33; New Hart’s Rules 2014, 197).
Write: 4 May 2026 or May 4, 2026
Speak: 4th of May 2026 or May 4th, 2026
However, when writing just the date without the month or year, use the ordinal form (Chicago 2024, 9.33; New Hart’s Rules 2014, 197).
We arrived at the resort on 15 June. By the twenty-fifth, our vacation was just about over.
Notes
Not addressed here is the year-month-day format as outlined by the International Organization for Standardization (ISO 8601). This omission is intentional because my focus is on running text (body text), and the year-month-day format is generally reserved for tabulated data, programming, file naming, and other data-focused usage. This standard was developed to prevent ambiguity for numeral-based dates like 07/08/26 (07.08.26), which can be interpreted as either July 8, 2026, or 7 August 2026 (International Organization for Standardization, n.d.; Chicago 2024, 9.37, 9.38). ISO 8601 specifies 2026-07-08 to indicate 8 July 2026 (July 8, 2026).
In some languages like Japanese and Korean, the year-month-day format, 2026年7月8日 and 2026년 7월 8일, respectively, is used in running text, but this format does not generally appear in English translations.
References
The Chicago Manual of Style. 2024. 18th ed. Chicago: University of Chicago Press.
International Organization for Standardization. n.d. “ISO 8601: Date and Time Format.” Accessed October 29, 2026. https://www.iso.org/iso-8601-date-and-time-format.html.
MLA (Modern Language Association of America). 2021. MLA Handbook. 9th ed. New York: Modern Language Association of America.
New Hart’s Rules: The Oxford Style Guide. 2014. 2nd ed. New York: Oxford University Press.
UNESCO. 2004. Style Manual for the Presentation of English-Language Texts Intended for Publication by UNESCO. 2nd ed. Paris: UNESCO.