USDA zone 8a in Oklahoma
USDA plant hardiness zone 8a covers 27 locations across Oklahoma (average annual extreme minimum 10 to 15 °F): Ardmore, OK, Burneyville, OK, Cache, OK, Calera, OK, Chattanooga, OK, Coleman, OK, and 21 more. Average last spring frost across this group ranges March 15 (Hugo) to April 13 (Hochatown), and growing seasons run 196–244 days (Hochatown to Hugo) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Oklahoma location's own frost dates; the printable planting calendar uses Idabel, this group's median-season location.
- USDA zone
- 8a10 to 15 °F
- Last frost range
- Mar 15–Apr 13avg, 32°F
- First frost range
- Oct 27–Nov 15avg, 32°F
- Growing season range
- 196–244days
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) |
|---|---|---|---|---|---|
| Ardmore | — | Ardmore 3ene Mesonet | Mar 18 | Nov 10 | 238 |
| Burneyville | Marietta, Thackerville, Greenville, Leon | Marietta 5sw | Apr 6 | Nov 2 | 211 |
| Cache | Medicine Park, Geronimo | Lawton Muni Ap | Apr 1 | Nov 5 | 217 |
| Calera | Utica | Durant 6sse Mesonet | Mar 19 | Nov 12 | 237 |
| Chattanooga | Loveland | Chattanooga | Apr 7 | Nov 2 | 205 |
| Coleman | Wapanucka, Milburn | Coleman 4w | Mar 31 | Nov 5 | 221 |
| Duncan | Comanche | Duncan | Mar 25 | Nov 7 | 225 |
| Durant | Caddo | Durant | Mar 31 | Nov 5 | 221 |
| Frederick | Harrold, Davidson, Oklaunion, Manitou, Hollister | Altus Afb | Mar 26 | Nov 10 | 229 |
| Gene Autry | Dougherty | Chickasaw Nra | Apr 4 | Oct 31 | 208 |
| Grandfield | — | Grandfield 3w Mesonet | Mar 31 | Nov 6 | 219 |
| Hastings | Addington | Waurika | Mar 24 | Nov 8 | 228 |
| Haworth | — | De Queen Sevier Co Ap | Mar 26 | Nov 5 | 226 |
| Hochatown | Wright, Swink | Battiest | Apr 13 | Oct 27 | 196 |
| Hugo | — | Hugo | Mar 15 | Nov 15 | 244 |
| Idabel * | Garvin, Millerton, Golden | Idabel | Mar 31 | Nov 3 | 221 |
| Indiahoma | — | Wichita Mtn Wr | Mar 28 | Nov 6 | 224 |
| Lane | Caney | Atoka | Apr 5 | Nov 1 | 211 |
| Lane | — | Mcgee Creek Dam | Mar 27 | Nov 9 | 228 |
| Lone Grove | Healdton, Davis, Wilson, Tatums, Hennepin, Ratliff, +3 more | Healdton 3 E | Apr 6 | Nov 1 | 204 |
| Madill | Lebanon, Kingston, Bee, Ravia, Mead, Earl | Madill | Mar 27 | Nov 8 | 227 |
| Nashoba | — | Tuskahoma | Apr 11 | Oct 27 | 199 |
| Sawyer | Fort Towson, Rattan, Antlers, Boswell, Finley, Moyers, +2 more | Antlers | Apr 3 | Nov 1 | 213 |
| Sugden | — | Waurika 1ene Mesonet | Mar 29 | Nov 5 | 223 |
| Tishomingo | — | Tishomingo 6n Mesonet | Mar 29 | Nov 5 | 222 |
| Velma | — | Velma 7nw Mesonet | Mar 28 | Nov 7 | 227 |
| Walters | Temple | Walters | Apr 1 | Nov 5 | 218 |
* Idabel 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 (Idabel, representative)
Computed from Idabel's average frost dates — the median-season location in this Oklahomazone 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 | Feb 3 – Feb 17 | Apr 7 – Apr 14 | Jun 6 – Jun 26 | — | matures comfortably |
| Pepper | Very tender | Jan 20 – Feb 3 | Apr 14 – Apr 21 | Jun 13 – Jul 13 | — | matures comfortably |
| Cucumber | Tender | Mar 3 – Mar 10 | Apr 7 – Apr 14 | May 27 – Jun 16 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | Apr 7 – Apr 14 | May 22 – Jun 6 | — | matures comfortably |
| Bush bean | Tender | — | Apr 7 – Apr 14 | May 27 – Jun 6 | Sep 4 – Sep 14 | matures comfortably |
| Sweet corn | Tender | — | Mar 31 – Apr 14 | May 30 – Jun 29 | — | matures comfortably |
| Basil | Very tender | Feb 17 – Mar 3 | Apr 7 – Apr 14 | May 7 – May 22 | — | matures comfortably |
| Lettuce | Half-hardy | Feb 17 – Mar 3 | Mar 3 – Mar 17 | Apr 17 – May 2 | Aug 21 – Sep 5 | matures comfortably |
| Pea | Hardy | — | Feb 17 – Mar 3 | Apr 13 – Apr 28 | Aug 11 – Aug 26 | matures comfortably |
| Spinach | Hardy | — | Feb 17 – Mar 3 | Mar 29 – Apr 8 | Aug 31 – Sep 10 | matures comfortably |
| Carrot | Half-hardy | — | Mar 10 – Mar 17 | May 9 – May 29 | Aug 1 – Aug 21 | matures comfortably |
| Broccoli | Half-hardy | Feb 3 – Feb 17 | Mar 3 – Mar 17 | Apr 27 – May 17 | Aug 6 – Aug 26 | matures comfortably |
Which crops fit this growing season
Using Idabel's own 221-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 (Idabel)
From NOAA's 1991–2020 Climate Normals at station USC00344451. 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 12 | Apr 28 | Oct 24 | Nov 6 | 196 |
| 32°F (freeze) | Mar 31 | Apr 18 | Nov 3 | Nov 20 | 221 |
| 28°F | Mar 13 | Apr 2 | Nov 13 | Dec 1 | 246 |
| 24°F | Feb 28 | Mar 19 | Nov 27 | Dec 17 | 273 |
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 27 locations is 5,485; Idabel's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 5,376 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,406 | cool-season crops (brassicas, greens) |
Hardiness zone 8a in Oklahoma
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. Oklahoma spans 4 hardiness zones in this dataset — see all Oklahoma locations for the full range, including zones6b, 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 Oklahoma?
- Zone 8a means an average annual extreme minimum winter temperature of 10 to 15 °F — the standard USDA measure of which perennials survive winter. 27 locations in Oklahoma fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Oklahoma's zone 8a is the growing season longest?
- Hugo runs the longest season on this page at about 244 days; Hochatown is shortest at about 196 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 Oklahoma's zone 8a?
- Using Idabel's frost dates (this page's median-season location): start seeds indoors about Feb 3 – Feb 17, then transplant outside about Apr 7 – Apr 14. 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 Oklahoma'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 27 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.