What zone am I in? USDA hardiness zone lookup
Type your ZIP code to find your planting zone on the 2023 USDA Plant Hardiness Zone Map. We'll remember it for the planner and every calendar on PlotPlan.
Typical last spring frost Apr 13 · first fall frost Oct 27. Adjust
What a hardiness zone actually measures
The USDA Plant Hardiness Zone Map sorts the country by one number: the average annual extreme minimum temperature, the coldest night of the year averaged over 30 winters. It was last updated in November 2023 using 1991–2020 data.
That makes zones a survival test for plants that stay in the ground through winter: perennial herbs, fruit trees, asparagus, garlic. A plant labelled "hardy to zone 5" should come through a typical zone 5 winter.
Annual vegetables like tomatoes and beans die at the first frost whatever your zone. For them, what matters is frost dates and season length, which the planting calendar works from.
USDA zone temperature chart
Average coldest-night range for each half-zone, with the typical frost dates PlotPlan uses as a starting point. Your selected zone is highlighted.
| Zone | Coldest night (°F) | Coldest night (°C) | Typical last spring frost | Typical first fall frost |
|---|---|---|---|---|
| 1a | -60 to -55 | -51 to -48 | Jun 12 | Aug 18 |
| 1b | -55 to -50 | -48 to -46 | Jun 5 | Aug 25 |
| 2a | -50 to -45 | -46 to -43 | May 30 | Sep 3 |
| 2b | -45 to -40 | -43 to -40 | May 23 | Sep 10 |
| 3a | -40 to -35 | -40 to -37 | May 20 | Sep 16 |
| 3b | -35 to -30 | -37 to -34 | May 13 | Sep 23 |
| 4a | -30 to -25 | -34 to -32 | May 12 | Sep 26 |
| 4b | -25 to -20 | -32 to -29 | May 5 | Oct 3 |
| 5a | -20 to -15 | -29 to -26 | Apr 30 | Oct 8 |
| 5b | -15 to -10 | -26 to -23 | Apr 23 | Oct 15 |
| 6a | -10 to -5 | -23 to -21 | Apr 20 | Oct 20 |
| 6b | -5 to 0 | -21 to -18 | Apr 13 | Oct 27 |
| 7a | 0 to 5 | -18 to -15 | Apr 8 | Oct 30 |
| 7b | 5 to 10 | -15 to -12 | Apr 1 | Nov 6 |
| 8a | 10 to 15 | -12 to -9 | Mar 26 | Nov 12 |
| 8b | 15 to 20 | -9 to -7 | Mar 19 | Nov 19 |
| 9a | 20 to 25 | -7 to -4 | Feb 22 | Dec 3 |
| 9b | 25 to 30 | -4 to -1 | Feb 15 | Dec 10 |
| 10a | 30 to 35 | -1 to 2 | Feb 1 | Dec 18 |
| 10b | 35 to 40 | 2 to 4 | Jan 25 | Dec 25 |
| 11a | 40 to 45 | 4 to 7 | Frost-free most years | Frost-free most years |
| 11b | 45 to 50 | 7 to 10 | Frost-free most years | Frost-free most years |
| 12a | 50 to 55 | 10 to 13 | Frost-free most years | Frost-free most years |
| 12b | 55 to 60 | 13 to 16 | Frost-free most years | Frost-free most years |
| 13a | 60 to 65 | 16 to 18 | Frost-free most years | Frost-free most years |
| 13b | 65 to 70 | 18 to 21 | Frost-free most years | Frost-free most years |
Frost dates are broad averages for each zone, drawn from NOAA 1991–2020 climate normals; coast, elevation and cities shift them by weeks.
Questions gardeners ask
What planting zone am I in?
Enter your ZIP code above. PlotPlan looks it up in data from the 2023 USDA Plant Hardiness Zone Map, produced with the PRISM Climate Group at Oregon State University, and saves the result for the planner and calendars.
What changed on the 2023 USDA map?
The 2023 map uses 1991–2020 weather data instead of 1976–2005. About half of the country shifted into the next warmer half-zone, largely because average coldest winter nights are milder than in the earlier period.
Does my zone tell me when to plant?
Only roughly. Zones measure winter cold, which decides which perennials survive. Planting dates depend on your frost dates, which is why PlotPlan links each zone to a typical last and first frost that you can override.
What is the difference between 7a and 7b?
Each zone is a 10°F band of average coldest-night temperature, split into two 5°F halves. Zone 7a averages 0 to 5°F on its coldest night; 7b averages 5 to 10°F.
Why do my neighbour and I have different conditions in the same zone?
Zones describe a region. Microclimates such as a south-facing wall, a frost pocket at the bottom of a slope, or urban heat can make your yard a half-zone warmer or colder than the map.