Hardiness zones in the 2023 ZIP file
USDA describes the map as 10°F zones split into 5°F half-zones, based on the average annual extreme minimum temperature. This list is every half-zone present in the PRISM 2023 ZIP table. Alaska, Hawaii, and Puerto Rico ZIP codes are not in that table.
- Zone 3a-40°F to -35°F · 5 ZIPs · 0 cities
- Zone 3b-35°F to -30°F · 204 ZIPs · 0 cities
- Zone 4a-30°F to -25°F · 783 ZIPs · 6 cities
- Zone 4b-25°F to -20°F · 1,256 ZIPs · 6 cities
- Zone 5a-20°F to -15°F · 2,393 ZIPs · 30 cities
- Zone 5b-15°F to -10°F · 2,865 ZIPs · 48 cities
- Zone 6a-10°F to -5°F · 5,183 ZIPs · 104 cities
- Zone 6b-5°F to 0°F · 5,263 ZIPs · 98 cities
- Zone 7a0°F to 5°F · 4,856 ZIPs · 91 cities
- Zone 7b5°F to 10°F · 3,840 ZIPs · 75 cities
- Zone 8a10°F to 15°F · 3,421 ZIPs · 72 cities
- Zone 8b15°F to 20°F · 3,375 ZIPs · 99 cities
- Zone 9a20°F to 25°F · 2,199 ZIPs · 59 cities
- Zone 9b25°F to 30°F · 2,085 ZIPs · 111 cities
- Zone 10a30°F to 35°F · 1,234 ZIPs · 111 cities
- Zone 10b35°F to 40°F · 751 ZIPs · 67 cities
- Zone 11a40°F to 45°F · 197 ZIPs · 21 cities
- Zone 11b45°F to 50°F · 11 ZIPs · 0 cities