Well, only a 19% chance of 12/13, but all the days are pretty low probability since there are so many possibilities. The spike on 12/13 is because it’s on a Friday, and historically DreamWorks has released most of its trailers on Fridays. In fact, 50% of its top 20 recent trailers have been released on Fridays. Because of this, there’s a good chance it will be released on either 12/13 or 12/20.
It would be awesome if they debuted it in front of The Hobbit on the 13th.