Frost dates · USDA zone 7b
Frost dates for Wilmington, DE
Wilmington, DE sees its last 32 °F night of spring around April 7 and its first of fall around November 4 — a 209-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Mar 26 | Nov 19 |
| Median — 1 year in 2 | Apr 7 | Nov 4 |
| 1 year in 10 | Apr 24 | Oct 21 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 209 days median, at least 189 in 9 years of 10, at least 229 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Mar 29 and first of Nov 15.
Wilmington planting calendar, 2027
Every row runs from the median last frost (Apr 7) and median first frost (Nov 4) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Jan 13 | Mar 10 | Jun 28 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 7 | May 7 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 24 | Mar 24 | May 8 | 45 from sow |
| Genovese BasilGenovese | Mar 10 | Apr 21 | Jun 20 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Feb 10 | Apr 14 | Jun 28 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 27 | Apr 21 | Jul 25 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Feb 10 | Apr 14 | Jun 28 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Feb 10 | Apr 14 | Jul 3 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Feb 10 | Apr 14 | Jul 3 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 24 | Mar 24 | Jun 2 | 70 from sow |
| TomatilloToma Verde | Feb 24 | Apr 14 | Jun 23 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 24 | Apr 14 | Jun 28 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 24 | Apr 14 | Jul 3 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Wilmington grow?
Each sauce, scheduled for a Wilmington container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Wilmington frost questions
When is the last frost in Wilmington, DE?
The median last 32 °F freeze at WILMINGTON PORTER RSCH, DE is April 7: half of years see a later one. One year in ten, a freeze still comes after April 24; nine years in ten, it comes after March 26. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Wilmington, DE?
The median first 32 °F freeze of fall is November 4. One year in ten it arrives before October 21; nine years in ten, before November 19.
How long is the growing season in Wilmington, DE?
209 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 189 days; one year in ten, at least 229 days.
What growing zone is Wilmington, DE?
USDA hardiness zone 7b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 19801. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Wilmington, DE?
Start Roma VF (determinate paste) seeds indoors around Feb 24 and transplant around Apr 14, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 24. First ripe fruit lands around Jun 28.
When should I plant peppers in Wilmington, DE?
Sow jalapeño indoors on a heat mat around Feb 10; transplant no earlier than Apr 14, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jun 28.
Nearby in Delaware
All Delaware frost dates → · How frost-date math drives a sowing calendar →