Last spring frost
Apr 11
Frost Dates for Detroit, AL
First fall frost
Oct 27
Growing season
198 days
Hardiness zone
7b
In an average year around Detroit, AL, the last spring frost (32°F) is about Apr 11 and the first fall frost is about Oct 27, giving roughly a 198-day growing season. To be safe most years, wait until Mar 26 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 7 | Apr 23 | Apr 7 |
| Freeze (32°F) | Apr 27 | Apr 11 | Mar 26 |
| Hard (28°F) | Apr 16 | Mar 31 | Mar 11 |
| Severe (24°F) | Apr 4 | Mar 16 | Feb 24 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 7 | May 2 | Apr 30 | Apr 26 | Apr 23 | Apr 20 | Apr 16 | Apr 12 | Apr 7 |
| 32°F | Apr 27 | Apr 22 | Apr 18 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Mar 31 | Mar 26 |
| 28°F | Apr 16 | Apr 10 | Apr 6 | Apr 3 | Mar 31 | Mar 27 | Mar 23 | Mar 18 | Mar 11 |
| 24°F | Apr 4 | Mar 30 | Mar 25 | Mar 20 | Mar 16 | Mar 11 | Mar 6 | Mar 1 | Feb 24 |
| 20°F | Mar 21 | Mar 15 | Mar 10 | Mar 5 | Mar 1 | Feb 26 | Feb 21 | Feb 14 | Feb 5 |
| 16°F | Mar 11 | Mar 4 | Feb 27 | Feb 20 | Feb 13 | Feb 7 | Feb 2 | Jan 28 | Jan 17 |
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 7 | Oct 19 | Oct 31 |
| Freeze (32°F) | Oct 15 | Oct 27 | Nov 10 |
| Hard (28°F) | Oct 22 | Nov 4 | Nov 25 |
| Severe (24°F) | Nov 1 | Nov 17 | Dec 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 24 | Oct 27 | Oct 31 |
| 32°F | Oct 15 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 10 |
| 28°F | Oct 22 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 13 | Nov 18 | Nov 25 |
| 24°F | Nov 1 | Nov 4 | Nov 8 | Nov 13 | Nov 17 | Nov 21 | Nov 26 | Dec 1 | Dec 7 |
| 20°F | Nov 9 | Nov 17 | Nov 23 | Nov 28 | Dec 2 | Dec 7 | Dec 13 | Dec 24 | Jan 1 |
| 16°F | Nov 22 | Dec 1 | Dec 8 | Dec 15 | Dec 23 | Dec 30 | Jan 3 | Jan 11 | Jan 25 |
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: Hamilton 3 S, Al, about 8.8 miles away@if(!empty($station['elevation_ft'])), at 435 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 Detroit, AL?
On average, the last spring frost (32°F) around Detroit, AL is about Apr 11. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 26.
When is the first frost in the fall?
The first fall frost around Detroit, AL typically arrives about Oct 27. 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 11 on average, or Mar 26 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 198 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 35552 Planting calendar → Alabama frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026