USDA Plant Hardiness Zone Map
USDA Agricultural Research Service and PRISM Climate Group at Oregon State University
The U.S. hardiness-zone reference for average annual extreme minimum temperature, with map graphics, GIS data, and ZIP-code lookup.
What you'll find here
U.S. hardiness zones
ZIP-code zone lookup
Map context
Minimum-temperature caveats
Specific data we draw from it: USDA zone, zone version, ZIP-code mapping, map citation.
Good to know
Zone caveats. Explain that hardiness zones are winter-minimum guidance, not full planting calendars.
Map attribution. Track whether a page uses official map graphics, raw zone data, or altered derived maps.
How to cite this source
Cite the 2023 USDA Plant Hardiness Zone Map and preserve USDA-ARS/OSU attribution when required.
License
USDA map graphics are public-domain U.S. government publications; underlying GIS datasets have attribution and alteration conditions.
Caution
Do not alter official zone boundaries or derived maps without the required disclaimer and logo handling.
Cited by plants
No catalog plant cites this source yet.