Looking for USDA plant hardiness zone shapefile

The USDA just issued brand new hardiness zone maps, an interactive web site, and ... shapefiles. I haven't actually looked at the shapefiles, but terms and conditions and download are all here

The news story about the new zones from AP on Yahoo can be found here

With some diligent work from several people, an open sourced version of the hardiness zones have been created. I found this link -

https://github.com/wboykinm/ophz/tree/master

Have you looked here http://www.hardiness-zone-map.com/? The map is implemented with overlays on Google maps. If you read the script that implements the map, you can find where the .png files are located. Not a pretty solution, but it might work.

[edit] I've searched a bit more and found shapefiles for annual mean minimum temperature . It's only a short hop from there to hardiness zone.