Frost Dates for Wilmington, DE
In Wilmington, DE, the average last spring frost is around Apr 7 and the average first fall frost around Nov 4, for a growing season of about 209 days. For frost-tender plants, wait until Apr 24, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Wilmington Porter Rsch, DE weather station, 3 miles away, elevation 270 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | Apr 24 | Oct 21 |
| 20% | Apr 18 | Oct 27 |
| 30% | Apr 13 | Oct 30 |
| 40% | Apr 10 | Nov 1 |
| 50% | Apr 7 | Nov 4 |
| 60% | Apr 5 | Nov 7 |
| 70% | Apr 2 | Nov 10 |
| 80% | Mar 31 | Nov 13 |
| 90% | Mar 26 | Nov 19 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | Apr 20 | Oct 24 |
| Frost / freeze (32°F) | Apr 7 | Nov 4 |
| Hard freeze (28°F) | Mar 29 | Nov 15 |
Planting calendar for Wilmington
Transplant Apr 14 – Apr 28
Transplant Apr 21 – May 5
Transplant Apr 21 – May 5
Transplant Apr 14 – Apr 28
Sow or transplant Apr 14 – Apr 28
Sow or transplant Apr 14 – Apr 28
Sow or transplant Apr 21 – May 5
Sow or transplant Mar 10 – Mar 24
Fall sowing Sep 9 – Oct 7
Fall sowing Sep 9 – Sep 30
Fall sowing Aug 26 – Sep 9
Sow or transplant Mar 10 – Mar 24
Fall sowing Aug 26 – Sep 23
Transplant Mar 24 – Apr 7
Fall sowing Aug 12 – Aug 26
Transplant Mar 17 – Mar 31
Fall sowing Aug 12 – Aug 26
Fall sowing Aug 12 – Aug 26
Fall sowing Sep 23 – Oct 14
Fall sowing Aug 26 – Sep 9
Plant Mar 10 – Mar 24
Based on the average last frost (Apr 7) and first frost (Nov 4). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.