Using Commas in Your Dates

How you write a date depends largely on where you learned to do so. How to punctuate that date, however, does not.

Americans tend to write dates listing the month before the day. Most of the rest of the world inverts those elements. Which way you choose to write a date affects how many commas, if any, are required. Adding the day of the week requires a comma, in any case. “We delivered the package on Friday, April 3rd, 2008.” “They took delivery Friday, 3 April 2008.”

When you write a date out, like the first of March, you need a comma only if you include the year. If you specify the first of March, 2012, you must insert a comma on either side of the year. If you want to indicate the first of March every year, you don't need a comma around the date at all unless the structure of the sentence demands one (as when it is part of or followed by a dependent clause like this sentence).

Should you prefer to start your dates with the month, you will need a comma between the day of that month and the year. As in the previous example, you don't need any commas if you don't name a year. “I will call my parents on April 5th.” “I will call my parents April 5th, 2008.” Both versions are written correctly. The former example simply implies that I will make a phone call every year on that date.

For some reason that I could not discover, when you write the date before the month you don't need any commas at all (again, unless the structure of the sentence demands one). Thus I could write that 5 April 2008 lives on in my memory. You can also skip commas if you list a month or season and the year. “Spring 2008 will prove a strong quarter for research and development.” “By July 2008 we intend to have proven our commitment to research.”

I have trouble remembering that last rule, as reading the sentence aloud seems to require a pause between the month and the year. Does anyone else have a date-writing or comma rule that poses a constant challenge?