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.
Your hardiness zone
10a
/tools/hardiness-zone/85003USDA 2023 Plant Hardiness Zone Map data, PRISM Climate Group / USDA-ARS. Zone boundaries simplified for display; not the official map.
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
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
You're in warm-season turf country
Regional windows from extension guidance. Treat them as a bracket to watch, not a date to spray.
Put down pre-emergent in late winter or early spring, as 2" soil temperature climbs toward 55°F and before your lawn greens up, with a second application 30 to 45 days later. Hold off on heavy nitrogen until soil temperature stays above 65°F and green-up is well underway. Feeding a dormant lawn just wastes the bag. In fall, watch for large patch as soil temperature drops toward 70°F. That is when a preventative fungicide actually works; spring is too late.
This is your ZIP code's centroid, not your exact address. Elevation, urban heat, and how close you are to water can all move your real zone by half a zone or more.
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.
Where the sources come from
- University of Georgia Extension: Warm-Season Lawn Establishment and Care
- Sod Solutions: Warm-Season Turf Dormancy and Green-Up
- Oregon State University Extension: Large Patch Disease Management (EPP-7324)
- 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).