USDA hardiness zones — 2023 map
Delaware hardiness zones — USDA planting zone map + what to grow
Zones 7a-8a · most of Delaware is zone 7b · Northeast region
DelawareUSDA zone range & map
On the 2023 USDA Plant Hardiness Zone Map, Delaware spans zones 7a-8a. The map shades the state from the northern Piedmont near Wilmington (zone 7a) through to the Atlantic coast and lower Delmarva (zone 8a). The single most common half-zone across the populated state is zone 7b — that is the figure to use if you only remember one number for Delaware. Delaware is small and mild, moderated by the Atlantic and Delaware Bay, with a long, productive mid-Atlantic season.
| USDA zone range | Zones 7a-8a |
|---|---|
| Most common zone | Zone 7b |
| Coldest area | the northern Piedmont near Wilmington (zone 7a) |
| Warmest area | the Atlantic coast and lower Delmarva (zone 8a) |
| Average last spring frost | mid-April |
| Average first fall frost | late October |
Source: USDA 2023 Plant Hardiness Zone Map (1991-2020 normals). Frost averages: NOAA/NCEI 1991-2020 climate normals. Local ZIP-level zones and frost dates can differ from these statewide figures.
Delaware hardiness zones by major city
Zones shift across Delaware with elevation and distance from the coast. Here is the 2023 USDA half-zone for the largest cities:
| City | USDA zone |
|---|---|
| Wilmington | Zone 7b |
| Dover | Zone 7b |
| Newark | Zone 7b |
| Rehoboth Beach | Zone 8a |
Need your exact zone? Run the ZIP-code zone finder for a precise half-zone and frost dates for your address.
ZIP-code zones in Delaware
Statewide ranges hide a lot. Tap your area for its exact USDA half-zone, last and first frost dates, and what to plant now:
- Newark 19711 — Zone 7b
- New Castle 19720 — Zone 7b
- Wilmington 19801 — Zone 7b
- Wilmington (West) 19805 — Zone 7b
- Dover 19901 — Zone 7b
- Lewes 19958 — Zone 8a
What Delaware's zone range means for planting
Your hardiness zone tells you which perennials, shrubs, and trees will survive a typical Delaware winter, and it anchors when tender crops can go outside. Because Delaware spans 7a-8a, two gardeners in the same state can have very different planting calendars.
- Pick perennials hardy to your local zone. Across most of Delaware that means at least zone 7b; gardeners in the northern Piedmont near Wilmington (zone 7a) should choose hardier plants.
- Anchor tender crops to your frost dates. With a last spring frost around mid-April and first fall frost around late October, set out tomatoes, peppers, and basil after the last frost and protect them before the first.
- Adjust for your microclimate. Urban heat, a south-facing slope, or a cold valley pocket can shift your effective zone and frost dates by a half-zone or more from the statewide figure.
Find your exact zone in Delaware
The 7a-8a range is statewide. Growli pins your hardiness zone and frost dates to your exact ZIP code and sends a push notification before any forecast frost night for your saved location.
Frequently asked questions
What hardiness zone is Delaware?
Delaware spans USDA hardiness zones 7a-8a on the 2023 USDA Plant Hardiness Zone Map. The most common zone — covering the largest share of the populated state — is zone 7b. The coldest areas are the northern Piedmont near Wilmington (zone 7a) and the warmest are the Atlantic coast and lower Delmarva (zone 8a).
When is the last frost in Delaware?
Across most of Delaware the average last spring frost falls around mid-April and the first fall frost around late October. These are statewide averages — colder, higher areas run later in spring and earlier in fall, so check a ZIP-level estimate for your exact spot.
What grows well in Delaware?
Delaware is small and mild, moderated by the Atlantic and Delaware Bay, with a long, productive mid-Atlantic season. Match plants to your local half-zone within the 7a-8a range: choose varieties hardy to at least zone 7b for reliable overwintering, and time tender crops around your local frost dates. The zone 7 planting guide lists vegetables, fruit, and ornamentals suited to most of the state.
Why does Delaware have more than one hardiness zone?
Hardiness zones track the average annual coldest temperature, which changes with latitude, elevation, distance from water, and urban heat. That is why Delaware ranges from the northern Piedmont near Wilmington (zone 7a) to the Atlantic coast and lower Delmarva (zone 8a) — a span of 7a-8a — even though it is a single state.
Did Delaware's hardiness zone change in 2023?
The USDA updated the Plant Hardiness Zone Map in November 2023 using 1991-2020 climate data. About half the country, including parts of Delaware, shifted to the next warmer half-zone versus the 2012 map. The 7a-8a range here reflects the current 2023 map. Always confirm your address against the official USDA map for plant-survival decisions.