My letter with the card had a return address in Washington DC on the envelope, but I seem to recall reading somewhere that the cards are printed in VA?? So I suppose it depends on how fast USPS will get mail to you. In my interview, everyone was being told the cards would be delivered in 1-2 weeks (there were US residents and Canadian residents ahead of me). Me getting the card today falls just within that 2 week period which also happened to include a federal holiday.

So... if your last interviews were Jul 8 the 2 week period would take you to July 22. Fingers crossed - oh... and don't forget to activate the cards if you do get them before you leave. My spouse had a trip to secondary because that was forgotten before the first trip across the land border - didn't have any issues flying.