2012 had a good Summer. A big leap in sales shows that there was a lot of activity in the late Spring therefore there were many closings in the summer. Look at July, with 48 Closings in 2012 verses 27 the previous year, I wonder if the warm winter helped that number.
If you notice a drop in February and March of 2012 this could be a result of Hurricane Irene and the Nor'easter in late October 2011.
I wonder why May 2011 had such fewer Sales than the previous year and 2012??