I think the important thing is to be consistent and that also the sentence should be clear. Personally I would never put a comma in a date in a sentence (at least without a comma after the date such as you would for a day that's in the week just past or coming), as it confuses the reading of the punctuation in the sentence. Commas wouldn't be such a problem in a date that's simply a heading on its own.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.