If you're going to list dates (the kind found on a calendar) in your writing, be consistent with the formatting.

If you express the date as month, day, and year, put a comma between the day and the year (e.g., August 10, 1999). Use a comma after the year if it is not at the end of a sentence.

To express the month and the year, separate them with a space (no comma) (e.g., August 1999).

If you use the "day month year" format in narrative text, no punctuation is needed between the elements (e.g., 14 February 2008). This is the preferred formatting for folks who do genealogical research because there is no confusion between years. (Do you mean 2009, 1909, or 1809 when you write, "09"?)

Also, use numbers for the date (not ordinals). Don't use "August 1st 2008."