USDA zone 9a in Alabama
USDA plant hardiness zone 9a covers 12 locations across Alabama (average annual extreme minimum 20 to 25 °F): Atmore, AL, Bay Minette, AL, Dothan, AL, Grand Bay, AL, Gulf Shores, AL, Headland, AL, and 6 more. Average last spring frost across this group ranges January 31 (Gulf Shores) to March 23 (Slocomb), and growing seasons run 231–340 days (Slocomb to Gulf Shores) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Alabama location's own frost dates; the printable planting calendar uses Mobile, this group's median-season location.
- USDA zone
- 9a20 to 25 °F
- Last frost range
- Jan 31–Mar 23avg, 32°F
- First frost range
- Jan 6–Dec 6avg, 32°F
- Growing season range
- 231–340days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Atmore | — | Atmore | Feb 28 | Nov 27 | 270 |
| Bay Minette | Perdido, Stapleton | Bay Minette | Feb 28 | Nov 25 | 272 |
| Dothan | Webb, Cowarts, Rehobeth, Taylor, Ashford, Midland, +1 more | Dothan Rgnl Ap | Mar 1 | Nov 24 | 270 |
| Grand Bay | Theodore, Bayou La Batre | Coden | Mar 13 | Nov 24 | 255 |
| Gulf Shores | — | Dauphin Is #2 | Jan 31 | Jan 6 | 340 |
| Headland | Columbia | Headland | Mar 5 | Nov 24 | 264 |
| Lockhart | — | Florala Muni Ap | Mar 4 | Nov 26 | 265 |
| Loxley | Gulf Shores, Orange Beach, Summerdale, Elberta, Robertsdale, Bon Secour, +3 more | Robertsdale | Mar 5 | Nov 23 | 264 |
| Mobile | Chickasaw | Mobile Dwtn Ap | Feb 21 | Dec 6 | 292 |
| Mobile * | Saraland, Semmes, Tillmans Corner | Mobile | Mar 3 | Nov 25 | 268 |
| Slocomb | — | Geneva #2 | Mar 23 | Nov 7 | 231 |
| Spanish Fort | Daphne, Fairhope, Point Clear, Magnolia Springs | Fairhope 2 Ne | Mar 10 | Nov 17 | 253 |
* Mobile is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Mobile, representative)
Computed from Mobile's average frost dates — the median-season location in this Alabamazone 9a group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Jan 6 – Jan 20 | Mar 10 – Mar 17 | May 9 – May 29 | — | matures comfortably |
| Pepper | Very tender | Jan 1 – Jan 6 | Mar 17 – Mar 24 | May 16 – Jun 15 | — | matures comfortably |
| Cucumber | Tender | Feb 3 – Feb 10 | Mar 10 – Mar 17 | Apr 29 – May 19 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Mar 10 – Mar 17 | Apr 24 – May 9 | — | matures comfortably |
| Bush bean | Tender | — | Mar 10 – Mar 17 | Apr 29 – May 9 | Sep 26 – Oct 6 | matures comfortably |
| Sweet corn | Tender | — | Mar 3 – Mar 17 | May 2 – Jun 1 | — | matures comfortably |
| Basil | Very tender | Jan 20 – Feb 3 | Mar 10 – Mar 17 | Apr 9 – Apr 24 | — | matures comfortably |
| Lettuce | Half-hardy | Jan 20 – Feb 3 | Feb 3 – Feb 17 | Mar 20 – Apr 4 | Sep 12 – Sep 27 | matures comfortably |
| Pea | Hardy | — | Jan 20 – Feb 3 | Mar 16 – Mar 31 | Sep 2 – Sep 17 | matures comfortably |
| Spinach | Hardy | — | Jan 20 – Feb 3 | Mar 1 – Mar 11 | Sep 22 – Oct 2 | matures comfortably |
| Carrot | Half-hardy | — | Feb 10 – Feb 17 | Apr 11 – May 1 | Aug 23 – Sep 12 | matures comfortably |
| Broccoli | Half-hardy | Jan 6 – Jan 20 | Feb 3 – Feb 17 | Mar 30 – Apr 19 | Aug 28 – Sep 17 | matures comfortably |
Which crops fit this growing season
Using Mobile's own 268-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Mobile)
From NOAA's 1991–2020 Climate Normals at station USW00013894. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Mar 17 | Apr 5 | Nov 13 | Dec 4 | 242 |
| 32°F (freeze) | Mar 3 | Mar 21 | Nov 25 | Dec 22 | 268 |
| 28°F | Feb 13 | Mar 13 | Dec 14 | Jan 17 | 303 |
| 24°F | Jan 30 | Mar 2 | Jan 3 | Feb 3 | 335 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 12 locations is 6,706; Mobile's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 6,719 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 10,139 | cool-season crops (brassicas, greens) |
Hardiness zone 9a in Alabama
Zone 9a means an average annual extreme minimum winter temperature of about 20 to 25 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Alabama spans 5 hardiness zones in this dataset — see all Alabama locations for the full range, including zones7b, 8a, 8b, 9b.
Explore zone 9a in other states at zone 9a, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 9a mean in Alabama?
- Zone 9a means an average annual extreme minimum winter temperature of 20 to 25 °F — the standard USDA measure of which perennials survive winter. 12 locations in Alabama fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Alabama's zone 9a is the growing season longest?
- Gulf Shores runs the longest season on this page at about 340 days; Slocomb is shortest at about 231 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Alabama's zone 9a?
- Using Mobile's frost dates (this page's median-season location): start seeds indoors about Jan 6 – Jan 20, then transplant outside about Mar 10 – Mar 17. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Alabama's zone 9a have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 12 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.