Originally back in March 2K Games and Irrational Games planned to release BioShock: Infinite in October, well unfortunately it's been delayed to February 26th, 2013. Which also means more time for polishing and really making it even better.
Ken Levine, Creative Director of Irrational Games, stated, “When we announced the release date of BioShock Infinite in March, we felt pretty good about the timing. Since then, we’ve uncovered opportunities to make Infinite into something even more extraordinary. Therefore, to give our talented team the time they need to deliver the best Infinite possible, we’ve decided to move the game’s release to February.”