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What's my USDA hardiness zone, and does my grass care?

Type a ZIP, a city, or your street address. You get your zone off the 2023 USDA Plant Hardiness Zone Map, the winter low behind it, and the part nobody else prints: what it does and doesn't tell you about the grass in your yard. Nothing you type is stored.

Type any of the three. An address pins you exactly. Nothing you type is stored, and nothing gets sent anywhere with your name on it.

Give us an address and the pin is your yard; give us a ZIP or city and it's the centroid. Either way the zone answer above doesn't depend on the map loading.

Zone band fill renders from
the PHZM 2023 vector layer

Every half-zone, and the winter low behind it

Each half-zone is a 5°F step in average annual extreme minimum temperature.
  • 3a-40°F to -35°F
  • 3b-35°F to -30°F
  • 4a-30°F to -25°F
  • 4b-25°F to -20°F
  • 5a-20°F to -15°F
  • 5b-15°F to -10°F
  • 6a-10°F to -5°F
  • 6b-5°F to 0°F
  • 7a0°F to 5°F
  • 7b5°F to 10°F
  • 8a10°F to 15°F
  • 8b15°F to 20°F
  • 9a20°F to 25°F
  • 9b25°F to 30°F
  • 10a30°F to 35°F
  • 10b35°F to 40°F
  • 11a40°F to 45°F
  • 11b45°F to 50°F
Zone data: USDA Plant Hardiness Zone Map, 2023 revision (PRISM Climate Group, Oregon State University).

Read this before you buy seed

Hardiness zone does not determine your grass type.

A hardiness zone is one number: the average coldest night of the year over 30 years. It predicts which perennials survive the winter. Cool-season versus warm-season turf is decided mostly by summer heat and humidity, which this map does not encode at all.

Zone 7b covers coastal Oregon and central Alabama. One is tall fescue country. The other is bermuda country. Same zone, opposite lawn.

So what does decide it

Three variables that beat the zone number

01
Summer night temperatures
Cool-season grass thins out when nights stay above roughly 70°F. That's what kills fescue in Atlanta, not winter.
02
Humidity and disease pressure
Humid summers bring brown patch and gray leaf spot. Dry summers of the same heat are far kinder to a cool-season stand.
03
Soil temperature, not the calendar
Every timing decision you make, from pre-emergent to the first feed to overseeding, tracks soil temperature at 2 inches. Two ZIPs in the same zone can be three weeks apart.

Your zone is a 30-year average. Your lawn only cares about this year.

LawnDominator watches your actual 2" soil temperature and growing degree days and tells you the week your pre-emergent window opens, when to feed, and when overseeding will actually take. No zone charts.

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Where the sources come from

  • Zone data: USDA Plant Hardiness Zone Map, 2023 revision (PRISM Climate Group, Oregon State University). Public domain, attribution requested.
  • Species adaptation: NC State TurfFiles, Purdue Turf Program, K-State Research & Extension, UGA Turfgrass.
  • Timing windows: state extension pre-emergent and fertility guidance, checked against our own soil-temperature model.
  • ZIP place names: GeoNames (CC BY 4.0).