USDA zone 8b in New Mexico
USDA plant hardiness zone 8b covers 3 locations across New Mexico (average annual extreme minimum 15 to 20 °F): Chaparral, NM, Las Cruces, NM, Organ, NM. Average last spring frost across this group ranges March 12 (Las Cruces) to April 24 (Organ), and growing seasons run 181–241 days (Organ to Las Cruces) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every New Mexico location's own frost dates; the printable planting calendar uses Chaparral, this group's median-season location.
- USDA zone
- 8b15 to 20 °F
- Last frost range
- Mar 12–Apr 24avg, 32°F
- First frost range
- Oct 24–Nov 13avg, 32°F
- Growing season range
- 181–241days
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) |
|---|---|---|---|---|---|
| Chaparral * | — | Orogrande | Mar 24 | Nov 7 | 225 |
| Las Cruces | Radium Springs, White Sands, Picacho Hills, Vado, Organ, Mesquite | State Univ | Mar 12 | Nov 13 | 241 |
| Organ | — | Las Cruces 20 N | Apr 24 | Oct 24 | 181 |
* Chaparral 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 (Chaparral, representative)
Computed from Chaparral's average frost dates — the median-season location in this New Mexicozone 8b 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 8 – Sep 18 | 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 25 – Sep 9 | matures comfortably |
| Pea | Hardy | — | Feb 10 – Feb 24 | Apr 6 – Apr 21 | Aug 15 – Aug 30 | matures comfortably |
| Spinach | Hardy | — | Feb 10 – Feb 24 | Mar 22 – Apr 1 | Sep 4 – Sep 14 | matures comfortably |
| Carrot | Half-hardy | — | Mar 3 – Mar 10 | May 2 – May 22 | Aug 5 – Aug 25 | matures comfortably |
| Broccoli | Half-hardy | Jan 27 – Feb 10 | Feb 24 – Mar 10 | Apr 20 – May 10 | Aug 10 – Aug 30 | matures comfortably |
Which crops fit this growing season
Using Chaparral's own 225-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 (Chaparral)
From NOAA's 1991–2020 Climate Normals at station USC00296435. 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 9 | Apr 26 | Oct 29 | Nov 9 | 201 |
| 32°F (freeze) | Mar 24 | Apr 9 | Nov 7 | Nov 19 | 225 |
| 28°F | Mar 8 | Mar 25 | Nov 17 | Nov 29 | 252 |
| 24°F | Feb 21 | Mar 15 | Nov 27 | Dec 10 | 278 |
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 3 locations is 5,425; Chaparral's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 5,464 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,597 | cool-season crops (brassicas, greens) |
Hardiness zone 8b in New Mexico
Zone 8b means an average annual extreme minimum winter temperature of about 15 to 20 °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. New Mexico spans 8 hardiness zones in this dataset — see all New Mexico locations for the full range, including zones5a, 5b, 6a, 6b, 7a, 7b, 8a.
Explore zone 8b in other states at zone 8b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 8b mean in New Mexico?
- Zone 8b means an average annual extreme minimum winter temperature of 15 to 20 °F — the standard USDA measure of which perennials survive winter. 3 locations in New Mexico fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in New Mexico's zone 8b is the growing season longest?
- Las Cruces runs the longest season on this page at about 241 days; Organ is shortest at about 181 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 New Mexico's zone 8b?
- Using Chaparral'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 New Mexico's zone 8b 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 3 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.