Expressing times

Dates in the middle of a sentence

When a MONTH_DAY, YEAR date appears in the middle of a sentence, add a comma after the year.
Recommended: The January 19, 2017, release of ...
However, if the date in the middle of the sentence consists of the month and year only, don't use a comma.
Recommended: The January 2017 release of ...

Why we prefer dates written out

In general, don't express months as numbers unless you don't have the option (in which case, see numeric-only date format). Different regions of the world put parts of the date in a different order for numeric dates. For example, a date written as 04/05/09 means different things in different regions:

• 
  In the UK, 04/05/09 means May 4, 2009, where the order is usually day, month, and then year.
  
• 
  In the US, 04/05/09 means April 5, 2009, where the order is usually month, day, and then year.
  
• 
  In some other parts of the world, 04/05/09 means May 9, 2004. Some regions write the year first, followed by the month and day.
  

For this reason, we recommend always using words to express dates. Expressing dates in numbers only (using slashes, periods, or hyphens as separators) can be confusing.
Recommended: February 12, 2017
Recommended: Sunday, February 12, 2017
Not recommended: 02.12.2017
Not recommended: 12/02/2017