What's the correct format for writing dates in scientific literature?

[Joe Carillo]

Question posted by Forum member Pipes as a private message (August 23, 2011):

Dear Mr. Carillo,

I would just like to seek clarification with regard to writing dates in Scientific Literature. Which of the two formats is correct: 24th June 2011 or 24th June, 2011? Our professor also prescribes this format—June 24th, 2011. Is that format still acceptable? Thank you!

Yours,
pipes

My reply to Pipes:

I don’t think any of the date formats you presented—including that of your professor—is acceptable in scientific literature. A telltale sign that they are nonstandard, unsystematic, and unsuitable for scientific purposes is the presence of the suffix “-th” after the day of the month, “24th.” You see, using serial endings for the day of the month—1st, 2nd, 3rd, 4th, and all the way to 31st—entails a lot of spelling variation that’s anathema to the systematic approach demanded by science.

             IMAGE SOURCE: WIKIPEDIA MANUAL OF STYLE


Although it’s by no means an internationally accepted full date format, what I think comes closest to the idea of writing dates scientifically is this popular format:

Full date: 24 June 2011
(without a comma after the day of the month)

Month and day only: 24 June
(also without a comma after the day of the month)

The above format, of course, differs from this conventional, nonscientific format that most of us have gotten used to:

June 24, 2011
(always with a comma after the day of the month)

Now, the international standard date and time notation prescribed by the ISO (International Organization for Standardization) actually differs greatly from all of the above formats.

The international standard date notation is: YYYY-MM-DD

where YYYY is the year in the usual Gregorian calendar, MM is the month of the year between 01 (January) and 12 (December), and DD is the day of the month between 01 and 31.

So, I would say that the more scientific format for “June 24, 2011” will be the ISO format, as follows:

2011-06-24

Obviously, though, such a format won’t look very good in nonscientific prose or exposition, so now that you ask me, I’d settle for the popular systematic format I presented earlier:

24 June 2011

For more details about the scientific format for dates, click this link to Markus Kuhn’s summary of the international standard date and time notation. I’m sure that your professor can learn a thing or two from it, and might just have a change of mind about the format he or she prescribes.