Frost dates / By state
Frost dates in Delaware
NOAA 1991–2020 normals for a 32 °F freeze. Your own yard can run a little either side.
Short answer
Across 7 NOAA weather stations in Delaware, the average last spring frost runs from March 29 at Lewes to April 11 at Greenwood 2NE. The first fall frost comes as early as October 30 at Greenwood 2NE and as late as November 14 at Lewes. Every station sits in planting zone 7b.
Find yours by ZIP code
The table below is by weather station. For the station nearest you, and your planting zone, type your ZIP code.
Delaware frost dates by weather station
| Station | Last spring frost | First fall frost | Frost-free | Zone nearby |
|---|---|---|---|---|
| Dover 30 ft | April 4 1 in 10 after April 17 | November 4 1 in 10 by October 23 | 214 days | 7b |
| Georgetown Sussex Co Airport 51 ft | April 4 1 in 10 after April 16 | November 6 1 in 10 by October 23 | 216 days | 7b |
| Greenwood 2NE 45 ft | April 11 1 in 10 after April 28 | October 30 1 in 10 by October 14 | 202 days | 7b |
| Lewes 10 ft | March 29 1 in 10 after April 9 | November 14 1 in 10 by November 1 | 230 days | 7b |
| Newark Ag Farm 106 ft | April 7 1 in 10 after April 21 | November 2 1 in 10 by October 19 | 209 days | 7b |
| Wilmington New Castle Co Airport 79 ft | April 7 1 in 10 after April 21 | November 1 1 in 10 by October 19 | 208 days | 7b |
| Wilmington Porter Rsch 270 ft | April 7 1 in 10 after April 24 | November 4 1 in 10 by October 21 | 211 days | 7b |
The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. Stations are NOAA's main weather stations, mostly airports, plus cooperative stations spread across the state. “Zone nearby” is the USDA 2023 zone of the nearest ZIP code within 10 miles. NOAA counts the frost season from August to July, so in the warmest places the “first fall” freeze lands after New Year.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
Other states
Alabama · Alaska · Arizona · Arkansas · California · Colorado · Connecticut · Florida · Georgia · Hawaii · Idaho · Illinois · Indiana · Iowa · Kansas · Kentucky · Louisiana · Maine · Maryland · Massachusetts · Michigan · Minnesota · Mississippi · Missouri · Montana · Nebraska · Nevada · New Hampshire · New Jersey · New Mexico · New York · North Carolina · North Dakota · Ohio · Oklahoma · Oregon · Pennsylvania · Rhode Island · South Carolina · South Dakota · Tennessee · Texas · Utah · Vermont · Virginia · Washington · West Virginia · Wisconsin · Wyoming
Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)