Frost dates in Delaware

Across Delaware's 7 NOAA stations with a frost every year, the typical last spring frost ranges from March 29 at Lewes (10 feet above sea level) to April 11 at Greenwood 2 NE (50 feet above sea level). The middle station's date is April 7.

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Last frost across Delaware

The frost-free season runs from 200 days at Greenwood 2 NE to 231 days at Lewes.

These are typical dates: in half of springs the last frost comes later. Each place's page, and each ZIP code lookup, also gives the late-year date, after which only 1 spring in 10 has a frost. That's the safer date for tender plants.

Frost dates for Delaware's larger places

Typical (1-in-2) dates. Each place's page has the early and late years, a planting calendar and a printable planner. Zones are for the ZIP code nearest each place's center.

Hardiness zones in Delaware

Delaware's 93 ZIP codes in the USDA list fall in zones 7a to 8a: 7a (1 percent), 7b (95 percent) and 8a (4 percent). Compared with the 2012 map, 87 percent of them moved to a warmer half zone and 13 percent stayed the same.

A hardiness zone is about the coldest night of winter, which decides which shrubs, trees and perennials survive. Frost dates are about spring and fall, which decide when to plant. You need both. Read more about what the zones mean and what changed in 2023.

Every NOAA station in Delaware

All 7 stations in Delaware with frost statistics in NOAA's 1991 to 2020 normals, from A to Z. Station names are usually a town, an airport, or a distance and direction from a town. Find one near you and at a similar elevation.

Typical (1-in-2) dates at 32°F. For the early and late years, and a planting calendar built from your own dates, look up your ZIP code.