Board Thread:Questions and Answers/@comment-79.151.145.94-20131019162549/@comment-4631119-20140128065754

If you haven't aware, Winter is happened between January through March, which means, in Northen Hemisphere countries, a year started with Winter season.

So it's just logical that the preview stated Fall 2012 then Winter 2013, which the first preview is for first part of Sakurasou which aired on Fall and the second preview is for the second part which aired on Winter.