Temperatures are up, and the frost-free seasons are longer all across America. Frost-free seasons are 5 to 21 days longer than they were on average from 1900 to 1960, according to a major national study.
http://ncadac.globalchange.gov/download/NCAJan11-2013-publicreviewdraft-fulldraft.pdf. That change is already a fact, not a projection. It's climate change that is here and now. And more is ahead.