What is a USDA plant hardiness zone?

Hardiness zones estimate the average annual extreme minimum winter temperature for a location. Gardeners and growers use them to judge which perennial plants are likely to survive winter outdoors. Zones are labeled like 7a or 10b.

How does US5 assign a zone to a ZIP code?

We use the USDA / PRISM plant hardiness map summarized to ZIP (or ZCTA) geography, then join that zone onto published US5 ZIP profiles. Only indexable ZIPs with a zone appear in this hub.

Why do some ZIPs show population and income here?

The zone label comes from the hardiness dataset. Population, median income, and home value are the same published ZIP metrics used on individual ZIP pages, so you can compare places inside a zone without leaving US5.

Is this gardening advice?

No. Zone membership is a climate classification, not a planting recommendation. Microclimates, elevation, and urban heat can differ inside a ZIP. Always check local guidance for plant selection.

USDA plant hardiness zones

Browse 19 zones on US5. Each zone page lists associated ZIP codes with population, income, and housing metrics, plus plain-language notes on what hardiness bands measure.

19 zones · 36,638 indexable ZIPs with a hardiness label

Plant hardiness zones answer a simple climate question: how cold does winter typically get? The USDA map (produced with PRISM climate normals) divides the country into half-zone bands so growers can compare winter extremes across regions.

On US5, each zone page lists indexable ZIPs in that band, sorted by population, with links into full ZIP profiles. That makes it easier to contrast coastal vs inland codes inside the same zone, or to move from a climate label into demographics and housing.

Browse by zone

Zone 10A

1,149 ZIPs · 23,319,795 people

Zone 10B

689 ZIPs · 15,896,472 people

Zone 11A

176 ZIPs · 3,827,975 people

Zone 11B

11 ZIPs · 77,440 people

Zone 12B

1 ZIPs · 16,721 people

Zone 3A

5 ZIPs · 4,089 people

Zone 3B

200 ZIPs · 291,962 people

Zone 4A

765 ZIPs · 1,729,137 people

Zone 4B

1,201 ZIPs · 4,115,345 people

Zone 5A

2,317 ZIPs · 9,286,677 people

Zone 5B

2,697 ZIPs · 14,963,040 people

Zone 6A

4,855 ZIPs · 35,646,945 people

Zone 6B

4,820 ZIPs · 38,252,118 people

Zone 7A

4,419 ZIPs · 34,371,750 people

Zone 7B

3,392 ZIPs · 43,334,057 people

Zone 8A

2,951 ZIPs · 29,412,969 people

Zone 8B

3,030 ZIPs · 32,234,100 people

Zone 9A

2,042 ZIPs · 22,746,497 people

Zone 9B

1,918 ZIPs · 34,156,501 people

How this list is built

Source: USDA Plant Hardiness Zone Map / PRISM ZIP summary. We attach each ZIP’s zone to the published US5 ZIP record, then aggregate indexable ZIPs by zone for this hub. Detail tables show up to the most populous ZIPs in the zone so the page stays readable.

A ZIP can cover mixed terrain. Zone assignment is a ZIP-level summary, not a parcel-level forecast. For methodology across US5 metrics, see Methodology.

Frequently asked questions

What is a USDA plant hardiness zone?: Hardiness zones estimate the average annual extreme minimum winter temperature for a location. Gardeners and growers use them to judge which perennial plants are likely to survive winter outdoors. Zones are labeled like 7a or 10b.
How does US5 assign a zone to a ZIP code?: We use the USDA / PRISM plant hardiness map summarized to ZIP (or ZCTA) geography, then join that zone onto published US5 ZIP profiles. Only indexable ZIPs with a zone appear in this hub.
Why do some ZIPs show population and income here?: The zone label comes from the hardiness dataset. Population, median income, and home value are the same published ZIP metrics used on individual ZIP pages, so you can compare places inside a zone without leaving US5.
Is this gardening advice?: No. Zone membership is a climate classification, not a planting recommendation. Microclimates, elevation, and urban heat can differ inside a ZIP. Always check local guidance for plant selection.