Forum:DWM cover date

This has just struck me, and I don't have a copy of DWM on hand to check this; but is the 'cover date' on the front of DWM the date that the issue was published or the date before the next one is? For example, DWM 264's cover date is 6 May. Is that the date it came out or the date before DWM 265 came out?

I know it sounds like stupid question, but I have a niggling feeling that it's the date before the next issue comes out. If this is the case, we need to fix the intro to the majority of DWM pages, and fix the infobox. MM/ Want to talk? 21:12, April 4, 2012 (UTC)
 * Already beat ya to this one, MM. See Forum:DWM issues: please help (re)write leads. (But yah, you're right.  Cover dates since almost forever have been expiration dates.  Most of our leads are totally wrong.)  11:56: Fri 06 Apr 2012