US Department of Agriculture (USDA) released an updated Plant Hardiness map

[MarkMazer]

FWIW:  https://planthardiness.ars.usda.gov/

Searchable by Zipcode

Mark Mazer
Hertford, NC
7B?

[janemcgary]

As traditional, the USDA ignores the fact that the US west contains the Sierra Nevada and Cascade mountain ranges, not to mention the Siskiyou region with its varied topography. We'll stick with Sunset zones out here.

[Diane Whitehead]

Yes.  Sunset considers topography and temperatures for the whole year.

USDA uses winter low temperatures only.  That is why my cool summer area has the same zone as places like Georgia.