Last year it was announced on February 27th.
In the past, the ACC has announced the matchups and who is home/away for years in advance, holding off only on announcing dates, which need to wait for schools to complete their OOC schedule, and for TV to decide what matchups they want and when they want them. They announced the matchups in 2004 for all conference games to be played from 2006-2015.
The OOC schedules for ACC schools were all messed up when the ACC decided late (in August I believe) to change their plan for the # of conference games to be played each year from 9 to 8. That drove a need for each ACC school to schedule an additional OOC game.
* VT scheduled a game with East Carolina to fill out their 2013 schedule on 10/16/12.
* Virginia scheduled a game with BYU (actually a home and home) to fill out their 2013 schedule on 11/7/12.
* Georgia Tech just signed Alabama A&M as their 12th opponent. They will be playing 2 FCS opponents in 2013. Could not find an FBS school willing to play in Atlanta.
* NC State scheduled Louisiana Tech as its 12th opponent in late November.
* Miami is finalizing its 12th game, which has no date yet but will be played against Savannah State. This was announced 12/3/12.
* Maryland filled out its 2013 schedule with games against Florida International and Old Dominion in October (though the dates were not finalized and contracts were not signed).
* Clemson is said to be close to finalizing their schedule for 2013. Like G Tech, they expect to play a second FCS school as their 12th opponent.
* Pittsburgh still needs a 12th opponent as well. They already have Villanova on their schedule so they probably will go with an FBS school. Or at least try to.
* Boston College still needs a 12th opponent. There is speculation it might be a MAC opponent in a game to be played at Alumni Stadium.
* UNC needs a 12th opponent. It could well be an FCS opponent as they have not scheduled one yet.
* Duke still has not scheduled a 12th opponent. They recently scheduled NC Central as their 11th opponent.
* Wake Forest also still has 2 openings. Not a good situation. Old Dominion has openings moving up to the FBS level. Would not be surprised to see both of these teams schedule them.
* Florida State still needs a 12th opponent. They had WVU until the Mountaineers pulled out late when they moved to the Big 12. They might be losing Nevada as well.
Syracuse still has not signed a 12th opponent either.
This recent BC article lays out schools that still have openings. There are slim pickings remaining. SU has one advantage over a number of other ACC schools in that it can schedule an FCS opponent with no issue affecting bowl eligibility, as it hasn't scheduled an FCS school for 2013 yet.