Here is a comparison of corn gdd's from 2012 thru 2017. This data is from a different location than the one i reported from in a previous post, they are seperated by about 2 miles..
 https://talk.newagtalk.com/forums/thread-view.asp?tid=725874&posts=5&highlight=corn &highlightmode=1#M6193010

(leslies east air temperature corn gdds 2012 - 2017.bmp)

leslies east air temperature corn gdds 2012 - 2017.bmp (2242KB - 47 downloads)