USDA zone 8a in Missouri
USDA plant hardiness zone 8a covers 1 location across Missouri (average annual extreme minimum 10 to 15 °F): Steele, MO. Average last spring frost across this group ranges March 24 and growing seasons run 227 days — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Missouri location's own frost dates; the printable planting calendar uses Steele, this group's median-season location.
- USDA zone
- 8a10 to 15 °F
- Last frost range
- Mar 24avg, 32°F
- First frost range
- Nov 6avg, 32°F
- Growing season range
- 227days
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) |
|---|---|---|---|---|---|
| Steele * | Finley, Cooter, Holland | Blytheville Muni Ap | Mar 24 | Nov 6 | 227 |
* Steele 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 (Steele, representative)
Computed from Steele's average frost dates — the median-season location in this Missourizone 8a 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 27 – Feb 10 | Mar 31 – Apr 7 | May 30 – Jun 19 | — | matures comfortably |
| Pepper | Very tender | Jan 13 – Jan 27 | Apr 7 – Apr 14 | Jun 6 – Jul 6 | — | matures comfortably |
| Cucumber | Tender | Feb 24 – Mar 3 | Mar 31 – Apr 7 | May 20 – Jun 9 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Mar 31 – Apr 7 | May 15 – May 30 | — | matures comfortably |
| Bush bean | Tender | — | Mar 31 – Apr 7 | May 20 – May 30 | Sep 7 – Sep 17 | matures comfortably |
| Sweet corn | Tender | — | Mar 24 – Apr 7 | May 23 – Jun 22 | — | matures comfortably |
| Basil | Very tender | Feb 10 – Feb 24 | Mar 31 – Apr 7 | Apr 30 – May 15 | — | matures comfortably |
| Lettuce | Half-hardy | Feb 10 – Feb 24 | Feb 24 – Mar 10 | Apr 10 – Apr 25 | Aug 24 – Sep 8 | matures comfortably |
| Pea | Hardy | — | Feb 10 – Feb 24 | Apr 6 – Apr 21 | Aug 14 – Aug 29 | matures comfortably |
| Spinach | Hardy | — | Feb 10 – Feb 24 | Mar 22 – Apr 1 | Sep 3 – Sep 13 | matures comfortably |
| Carrot | Half-hardy | — | Mar 3 – Mar 10 | May 2 – May 22 | Aug 4 – Aug 24 | matures comfortably |
| Broccoli | Half-hardy | Jan 27 – Feb 10 | Feb 24 – Mar 10 | Apr 20 – May 10 | Aug 9 – Aug 29 | matures comfortably |
Which crops fit this growing season
Using Steele's own 227-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 (Steele)
From NOAA's 1991–2020 Climate Normals at station USW00053869. 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 | Apr 4 | Apr 20 | Oct 26 | Nov 9 | 204 |
| 32°F (freeze) | Mar 24 | Apr 10 | Nov 6 | Nov 22 | 227 |
| 28°F | Mar 11 | Mar 30 | Nov 18 | Dec 8 | 252 |
| 24°F | Feb 28 | Mar 18 | Dec 3 | Jan 1 | 281 |
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 1 locations is 5,221; Steele's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 5,221 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,099 | cool-season crops (brassicas, greens) |
Hardiness zone 8a in Missouri
Zone 8a means an average annual extreme minimum winter temperature of about 10 to 15 °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. Missouri spans 6 hardiness zones in this dataset — see all Missouri locations for the full range, including zones5b, 6a, 6b, 7a, 7b.
Explore zone 8a in other states at zone 8a, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 8a mean in Missouri?
- Zone 8a means an average annual extreme minimum winter temperature of 10 to 15 °F — the standard USDA measure of which perennials survive winter. 1 location in Missouri fall in this zone. It does not set planting dates; see the frost calendar below for that.
- When should I plant tomatoes in Missouri's zone 8a?
- Using Steele's frost dates (this page's median-season location): start seeds indoors about Jan 27 – Feb 10, then transplant outside about Mar 31 – Apr 7. 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 Missouri's zone 8a 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 1 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.