Frost/Freeze - Average Last Date During Spring
Here are the average last frost/freeze dates across the U.S. from 1980-81 to 2009-10. This information is courtesy of the National Oceanic and Atmospheric Administration.
Freeze protection equipment - see Freeze Miser and look into pipe that expands in freezing weathers (such as WIRSBO pipe).
Click on the map below to go to the full size image file.
Here's a new NOAA ARCGIS map to mouse over for statistical information.