Question 1

Can one ZIP code cover more than one hardiness zone?

Accepted Answer

Yes. Many ZIP codes span enough elevation or terrain that more than one USDA hardiness zone appears inside the same code. A single zone number for a ZIP is an average or centroid shortcut. Use the map on this page after you look up your ZIP or location to see how zones change nearby—not just one label for the whole code.

Question 2

Why might my zone differ from a neighbor’s?

Accepted Answer

Hardiness zones follow extreme winter cold, which shifts with elevation, cold-air drainage, and local terrain—especially in the western U.S. and other hilly areas. Your neighbor a mile away (or hundreds of feet higher or lower) can sit in a different half-zone. Treat your map result as the planning zone for your spot, not a street-wide constant.

Question 3

Is this the current USDA Plant Hardiness Zone Map?

Accepted Answer

Yes. Diggin Up uses the official USDA Plant Hardiness Zone dataset from the December 2023 map update, produced with USDA Agricultural Research Service and Oregon State University PRISM Climate Group data. Older printed guides or websites may still show 2012 or 1990 zones; those can disagree with what you see here.

Question 4

What’s the difference between the “a” and “b” half-zones?

Accepted Answer

Each numbered zone spans about 10°F of average annual extreme minimum temperature and is split into “a” and “b” half-zones of about 5°F. The “a” half is the colder side of that zone; the “b” half is the warmer side. Plant tags that list a range (for example 5–8) usually mean the plant is expected to survive winters in those zones.

Question 5

What plants should I choose for my zone?

Accepted Answer

Use your zone to screen perennials, trees, shrubs, vines, and other plants that must survive your coldest winters—match the coldest zone on the plant tag to yours or a colder one. Zone alone does not tell you heat tolerance, soil, water, or when to plant annual vegetables; those need other tools and local knowledge.

Question 6

How do I use the hardiness zone map on this page?

Accepted Answer

Enter a ZIP code or use your current location to center the map and read the zone at that point. Then pan and zoom to compare nearby areas—especially if your garden sits on a hillside, in a valley, or far from the ZIP centroid—so you are not relying on a single number for a wide area.

USDA Plant Hardiness Zone 2026 by Location or Zip