Refering to the data from this link.
http://talk.newagtalk.com/forums/thread-view.asp?tid=373158&posts=12&highlight=snow&highlightmode=1#M2959029

  I went over the soil temperatures from 11/1/2012 to 3/11/2013.
 Temperature were recorded every 15 minutes. There was 12544 data points.
 The criteria i used for the cycle was the temperature had to start out at less than 30 degrees F and go past 32 degees. I found two cycles that qualifed, both of which occured last fall in nov. and  dec.
 Of the 12544 data points 1700 were more than 32 degrees, 8154 points were less than 30 degrees and 2690 points  between 30 - 32 degrees.