Planting zone by ZIP code
Your USDA hardiness zone tells you which perennials, shrubs and trees survive your winters. Enter a ZIP to get your zone from the 2023 USDA map, along with the frost dates that actually decide when to plant.
From coldest night to zone
Zone 6b
Peaches become possible; rosemary does not survive outdoors.
Every 10°F is one zone; every 5°F is a half zone. That's the whole formula.
Same zone, different season
Zones only look at one number: the coldest night. Seattle (98101) and Dallas (75201) winters are both mild enough to be zone 8b–9a, yet Seattle's last frost averages mid-March while Dallas's is early March, and Seattle's cool summers struggle to ripen melons that Dallas grows easily.
Likewise Denver (6a) and Chicago (6b) sit a half zone apart, but Denver's frost-free season is about 165 days against Chicago's 208, because of altitude and dry air.
Use your zone to choose perennials, fruit trees and shrubs. Use your frost dates to time vegetables and annuals.
USDA zone temperature ranges
| Zone | Average coldest night | a | b |
|---|---|---|---|
| Zone 1 | -60 to -50°F | -60 to -55°F | -55 to -50°F |
| Zone 2 | -50 to -40°F | -50 to -45°F | -45 to -40°F |
| Zone 3 | -40 to -30°F | -40 to -35°F | -35 to -30°F |
| Zone 4 | -30 to -20°F | -30 to -25°F | -25 to -20°F |
| Zone 5 | -20 to -10°F | -20 to -15°F | -15 to -10°F |
| Zone 6 | -10 to 0°F | -10 to -5°F | -5 to 0°F |
| Zone 7 | 0 to 10°F | 0 to 5°F | 5 to 10°F |
| Zone 8 | 10 to 20°F | 10 to 15°F | 15 to 20°F |
| Zone 9 | 20 to 30°F | 20 to 25°F | 25 to 30°F |
| Zone 10 | 30 to 40°F | 30 to 35°F | 35 to 40°F |
| Zone 11 | 40 to 50°F | 40 to 45°F | 45 to 50°F |
| Zone 12 | 50 to 60°F | 50 to 55°F | 55 to 60°F |
| Zone 13 | 60 to 70°F | 60 to 65°F | 65 to 70°F |
Hardiness zone FAQ
What is my planting zone by ZIP code?
Enter your ZIP code on this page to see your zone from the 2023 USDA Plant Hardiness Zone Map, which the USDA Agricultural Research Service produced with Oregon State University's PRISM Climate Group.
What does a hardiness zone mean?
A zone is based on the average coldest winter night over 1991–2020. Each zone spans 10°F and each half zone (a or b) spans 5°F. A plant rated "hardy to zone 6" should survive winters where the coldest night averages −10°F to 0°F.
Can I use my hardiness zone to decide when to plant vegetables?
Only roughly. Zones measure winter cold, not the length of the season or when spring frost ends. For planting dates, use your frost dates, which Seasonwise shows for the same ZIP code.
Did the hardiness zones change in 2023?
Yes. The 2023 map uses 1991–2020 data instead of 1976–2005. According to the USDA, about half of the country shifted into a warmer half zone, mostly because of more complete data and warmer winter lows.