What Hardiness Zone Is Delaware?

USDA 2023 Plant Hardiness Zone Map · 93 ZIP codes · Data updated 2026-10-28

Quick answer

Delaware spans USDA hardiness zones 7a–8a on the 2023 Plant Hardiness Zone Map. The most common zone is 7b, covering 95% of Delaware's ZIP codes. Zone 7b means the coldest night of an average winter reaches 5°F to 10°F (−15°C to −12°C). Enter your ZIP code for your exact zone.

Delaware hardiness zones by share of ZIP codes

Zone 7a1% · 1 ZIP

Zone 7b95% · 88 ZIPs

Zone 8a4% · 4 ZIPs

What the zones mean for Delaware gardeners

Same zone, different frost dates: within zone 7b, the median last spring frost ranges from March 29 at Lewes to April 11 at Greenwood 2NE, 13 days apart. Your zone tells you which perennials survive winter; your frost dates tell you when to plant.

Hardiness zones for 7 towns in Delaware

Each NOAA weather station is shown with the USDA zone of the nearest ZIP code (within 8 miles). Coldest night is the zone's range for the average annual extreme minimum temperature. Click a column to sort.

Filter by town


Dover	7b	5°F to 10°F	30	Apr 4	Nov 4
Georgetown Sussex County Airport	7b	5°F to 10°F	51	Apr 4	Nov 6
Greenwood 2NE	7b	5°F to 10°F	45	Apr 11	Oct 30
Lewes	7b	5°F to 10°F	10	Mar 29	Nov 14
Newark Agricultural Farm	7b	5°F to 10°F	106	Apr 7	Nov 2
Wilmington New Castle County Airport	7b	5°F to 10°F	79	Apr 7	Nov 1
Wilmington Porter Rsch	7b	5°F to 10°F	270	Apr 7	Nov 4

Frequently asked questions

What hardiness zone is Delaware?

Delaware is in USDA hardiness zones 7a–8a on the 2023 USDA Plant Hardiness Zone Map. Zone 7b is the most common, covering 95% of Delaware's ZIP codes, and zone 8a covers 4%. Enter your ZIP code for your exact zone.

What does zone 7b mean?

Zone 7b means the average annual extreme minimum temperature, the coldest night of a typical winter, is 5°F to 10°F (−15°C to −12°C). Perennials, shrubs and trees rated for zone 7b or colder should survive winter there.

Did Delaware's hardiness zones change in 2023?

The USDA released a new Plant Hardiness Zone Map in November 2023, based on 1991–2020 temperatures instead of 1976–2005. About half of the United States shifted half a zone warmer. Check your ZIP code here, because plant tags and older books may still list your 2012 zone.

When should I plant in zone 7b?

Hardiness zones don't set planting dates; frost dates do. Inside zone 7b in Delaware, the median last spring frost varies from March 29 to April 11. Look up your local frost dates and plant tender crops such as tomatoes after the 10%-risk last-frost date.

Zone and frost dates: use both

Your hardiness zone answers one question: will this plant survive the winter here? Choose perennials, shrubs, trees and bulbs rated for your zone or a colder one. For vegetables and annuals, what matters is the length of the frost-free season. See Delaware frost dates by town, or get a planting calendar for your ZIP code with start-indoors, transplant and sowing dates for 30 crops.

Sources and method

Zones are from the USDA 2023 Plant Hardiness Zone Map ZIP-code files published by the PRISM Climate Group, Oregon State University, based on 1991–2020 minimum temperatures. ZIP codes are assigned to states by USPS prefix. Town zones use the ZIP code nearest each NOAA 1991–2020 Climate Normals station. This is an independent tool, not an official USDA site. Full methodology.