The National Climatic Data Center tracks freeze/frost dates for the entire United States and releaed sometime ago the complete data from 1970 through 2000. That data is freely available but is in a computer readable format.
A long time ago I wrote software to read it, parse the information and present to the user their own local frost dates information. I should go back to the NOAA site and see if I can find that data again, maybe I can make this a feature for ATP.
Ahh, here it is:
http://cdo.ncdc.noaa.gov/cgi-b...
The raw data is this:
http://cdo.ncdc.noaa.gov/clima...
Raleigh Durham airport is:
90% chance of a frost before March 25th.
50% chance before April 10th.
10% change around April 25th.
For last dates, RDU is:
90% chance of a frost by Nov 10th.
50% chance by Oct 28.
10% change by Oct 14.
