Last spring frost
Apr 4
Frost Dates for Smyrna, DE
First fall frost
Nov 4
Growing season
214 days
Hardiness zone
7b
In an average year around Smyrna, DE, the last spring frost (32°F) is about Apr 4 and the first fall frost is about Nov 4, giving roughly a 214-day growing season. To be safe most years, wait until Mar 22 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 5 | Apr 17 | Apr 3 |
| Freeze (32°F) | Apr 17 | Apr 4 | Mar 22 |
| Hard (28°F) | Apr 5 | Mar 25 | Mar 8 |
| Severe (24°F) | Mar 27 | Mar 13 | Feb 26 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 29 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 | Apr 3 |
| 32°F | Apr 17 | Apr 12 | Apr 9 | Apr 6 | Apr 4 | Apr 1 | Mar 31 | Mar 28 | Mar 22 |
| 28°F | Apr 5 | Apr 1 | Mar 30 | Mar 27 | Mar 25 | Mar 22 | Mar 19 | Mar 15 | Mar 8 |
| 24°F | Mar 27 | Mar 22 | Mar 19 | Mar 16 | Mar 13 | Mar 10 | Mar 6 | Mar 2 | Feb 26 |
| 20°F | Mar 19 | Mar 14 | Mar 9 | Mar 6 | Mar 3 | Feb 28 | Feb 25 | Feb 19 | Feb 8 |
| 16°F | Mar 9 | Mar 3 | Feb 27 | Feb 22 | Feb 17 | Feb 11 | Feb 6 | Feb 1 | Jan 24 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 12 | Oct 25 | Nov 6 |
| Freeze (32°F) | Oct 23 | Nov 4 | Nov 18 |
| Hard (28°F) | Nov 3 | Nov 16 | Dec 3 |
| Severe (24°F) | Nov 11 | Nov 30 | Dec 20 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 12 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 6 |
| 32°F | Oct 23 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
| 28°F | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 19 | Nov 22 | Nov 27 | Dec 3 |
| 24°F | Nov 11 | Nov 17 | Nov 21 | Nov 25 | Nov 30 | Dec 3 | Dec 7 | Dec 12 | Dec 20 |
| 20°F | Nov 25 | Dec 1 | Dec 5 | Dec 10 | Dec 16 | Dec 20 | Dec 25 | Jan 1 | Jan 7 |
| 16°F | Dec 10 | Dec 19 | Dec 25 | Dec 30 | Jan 2 | Jan 7 | Jan 12 | Jan 18 | Jan 28 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Dover, De, about 10.7 miles away@if(!empty($station['elevation_ft'])), at 30 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Smyrna, DE?
On average, the last spring frost (32°F) around Smyrna, DE is about Apr 4. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 22.
When is the first frost in the fall?
The first fall frost around Smyrna, DE typically arrives about Nov 4. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 4 on average, or Mar 22 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 214 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 19977 Planting calendar → Delaware frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026