In Delaware, the last spring frost usually comes between April 7 and April 18, and the first fall frost between October 24 and November 4, depending on where you live. Most of Delaware is in USDA hardiness zones 7b to 8a.
Find the frost dates for your ZIP code
Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Frost dates for Delaware cities
Dates come from the NOAA weather station closest to each city. The last spring frost and first fall frost are the typical dates, with a 30% chance of frost after (or before) them. The safer planting date has only a 10% chance of a later spring frost: use it for tender plants like tomatoes, peppers and basil.
| City | Zone | Last frost | Safer date | First frost |
|---|---|---|---|---|
| Wilmington | 7b | April 13 | April 24 | Oct. 30 |
| Dover | 7b | April 9 | April 17 | Oct. 31 |
| Newark | 7b | April 14 | April 21 | Oct. 28 |
| Middletown | 7b | April 12 | April 21 | Oct. 28 |
| Milford | 7b | April 18 | April 28 | Oct. 24 |
| Seaford | 7b | April 18 | April 28 | Oct. 24 |
| Georgetown | 7b | April 9 | April 16 | Oct. 31 |
Frost dates can differ between nearby towns because of elevation, terrain and distance from water. For the most accurate dates, look up your own ZIP code.
Growing zones in Delaware
Most of Delaware is in USDA hardiness zones 7b to 8a. A typical frost-free growing season lasts about 217 days, longer in the warmest areas and shorter in the coldest.
Find planting dates for the main zones in Delaware:
- Zone 7 (about 95% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
- Zone 8 (about 5% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
See all crops in our planting guides, or build a planting calendar for your ZIP code.
How to use frost dates
- Cool-season crops such as peas, lettuce, spinach and onions can go in several weeks before your last spring frost.
- Warm-season crops such as tomatoes, peppers, squash and beans wait until after it, when the soil has warmed.
- Fall crops are timed back from your first fall frost, and garlic and tulips are planted around it.
- Frost dates are averages. Check the forecast before setting out tender plants.
Frequently asked questions
When is the last frost in Delaware?
It depends on where you live. Across most of Delaware, the last spring frost comes between April 7 and April 18. In Wilmington, it is around April 13.
When is the first frost in Delaware?
Across most of Delaware, the first fall frost comes between October 24 and November 4. In Wilmington, it is around October 30.
What planting zone is Delaware?
Most of Delaware is in USDA hardiness zones 7b to 8a. Enter your ZIP code above to find your exact zone.
When can I plant tomatoes in Delaware?
Plant tomatoes outside after your last frost, once nights stay above 50 °F. In Wilmington, the safer date, with only a 10% chance of a later frost, is around April 24. See when to plant tomatoes in zone 7.
Sources. Frost dates come from the nearest NOAA weather station to each city or ZIP code. Zones come from the 2023 USDA Plant Hardiness Zone Map ZIP code data. Our zone lookup is not the official USDA map.