Rainbow, AL planting calendar
- USDA zone
- 8a10 to 15 °F
- Last frost
- Mar 19avg, 32°F
- First frost
- Nov 13avg, 32°F
- Growing season
- 240days
Rainbow, Alabama is in USDA plant hardiness zone 8a. Its average last spring frost is around March 19 and the first fall frost around November 13, giving a growing season of about 240 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Rainbow planting calendar
Each crop's windows are counted from Rainbow's average frost dates. 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.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Jan 22 – Feb 5 | Mar 26 – Apr 2 | May 25 – Jun 14 | — |
| Pepper | Very tender | Jan 8 – Jan 22 | Apr 2 – Apr 9 | Jun 1 – Jul 1 | — |
| Cucumber | Tender | Feb 19 – Feb 26 | Mar 26 – Apr 2 | May 15 – Jun 4 | — |
| Summer squash / zucchini | Tender | — | Mar 26 – Apr 2 | May 10 – May 25 | — |
| Bush bean | Tender | — | Mar 26 – Apr 2 | May 15 – May 25 | Sep 14 – Sep 24 |
| Sweet corn | Tender | — | Mar 19 – Apr 2 | May 18 – Jun 17 | — |
| Basil | Very tender | Feb 5 – Feb 19 | Mar 26 – Apr 2 | Apr 25 – May 10 | — |
| Lettuce | Half-hardy | Feb 5 – Feb 19 | Feb 19 – Mar 5 | Apr 5 – Apr 20 | Aug 31 – Sep 15 |
| Pea | Hardy | — | Feb 5 – Feb 19 | Apr 1 – Apr 16 | Aug 21 – Sep 5 |
| Spinach | Hardy | — | Feb 5 – Feb 19 | Mar 17 – Mar 27 | Sep 10 – Sep 20 |
| Carrot | Half-hardy | — | Feb 26 – Mar 5 | Apr 27 – May 17 | Aug 11 – Aug 31 |
| Broccoli | Half-hardy | Jan 22 – Feb 5 | Feb 19 – Mar 5 | Apr 15 – May 5 | Aug 16 – Sep 5 |
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.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00013154. 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 (p10 for spring, p90 for fall) — 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 | Apr 1 | Apr 21 | Nov 3 | Nov 18 | 215 |
| 32°F (freeze) | Mar 19 | Apr 7 | Nov 13 | Dec 1 | 240 |
| 28°F | Mar 4 | Mar 24 | Nov 27 | Dec 23 | 268 |
| 24°F | Feb 17 | Mar 15 | Dec 13 | Jan 11 | 299 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
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. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 5,448 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,524 | cool-season crops (brassicas, greens) |
Hardiness zone 8a
Rainbow sits in USDA plant hardiness zone 8a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 10 to 15 °F. That number 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.
Explore more places in zone 8a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Rainbow?
- Rainbow, Alabama is in USDA plant hardiness zone 8a on the 2023 map (average annual extreme minimum temperature 10 to 15 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Rainbow?
- The average (median) last spring frost at 32°F is around March 19, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as April 7, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Rainbow?
- The average first fall frost at 32°F is around November 13. That leaves a growing season of about 240 days between the average last spring and first fall frosts.
- When should I start tomatoes in Rainbow?
- Start tomato seeds indoors about Jan 22 – Feb 5 and transplant them outside about Mar 26 – Apr 2, once the danger of frost has passed. Estimated first harvest is around May 25 – Jun 14.
- How long is the growing season in Rainbow?
- About 240 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~March 19) and the average first fall frost (~November 13). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00013154 (Gadsden, 5.4 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this 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.