What does USDA hardiness zone 6a mean in New Mexico?

Zone 6a means an average annual extreme minimum winter temperature of −10 to −5 °F — the standard USDA measure of which perennials survive winter. 29 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 6a is the growing season longest?

Springer runs the longest season on this page at about 164 days; Red River is shortest at about 77 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 6a?

Using Reserve's frost dates (this page's median-season location): start seeds indoors about Apr 4 – Apr 18, then transplant outside about Jun 6 – Jun 13. 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 6a 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 29 locations listed (see the table above for each location's own dates).

USDA zone 6a in New Mexico

−10 to −5 °F avg. annual extreme minimum · 29 locations in this group · NOAA 1991–2020 normals

USDA plant hardiness zone 6a covers 29 locations across New Mexico (average annual extreme minimum −10 to −5 °F): Angel Fire, NM, Angel Fire, NM, Aragon, NM, Canjilon, NM, Fence Lake, NM, Gallup, NM, and 23 more. Average last spring frost across this group ranges April 30 (Springer) to June 19 (Red River), and growing seasons run 77–164 days (Red River to Springer) — 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 Reserve, this group's median-season location.

USDA zone: 6a−10 to −5 °F
Last frost range: Apr 30–Jun 19avg, 32°F
First frost range: Sep 7–Oct 11avg, 32°F
Growing season range: 77–164days

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.

Own frost dates per location.
Location	Also covers	Nearest station	Last frost	First frost	Season (days)
Angel Fire	Eagle Nest, Ute Park	Eagle Nest	Jun 16	Sep 14	87
Angel Fire	Mora	Ocate 2 Nw	May 26	Sep 26	121
Aragon	Luna	Luna Rs	Jun 17	Sep 21	93
Canjilon	—	Tierra Amarilla 4 N	Jun 11	Sep 20	98
Fence Lake	—	Fence Lake	May 31	Oct 1	122
Gallup	Pinehaven, Sundance, Fort Wingate, Purty Rock	Gallup Muni Ap	May 31	Sep 28	119
Grenville	—	Pasamonte	May 5	Oct 7	153
Homestead	—	Augustine 2e	May 19	Oct 4	137
Hyde Park	—	Pecos Nm	May 15	Oct 3	138
Lybrook	—	Star Lake	May 28	Sep 28	121
Maxwell	—	Maxwell 3 Nw	May 17	Oct 1	135
McIntosh	Moriarty, Estancia	Estancia 4n	May 18	Oct 1	135
Mora	Truchas, PeÃ±asco	Gascon	May 28	Sep 26	119
Mountain View	—	El Morro Natl Mon	Jun 3	Sep 27	114
Ojo Encino	—	Torreon Navajo Mission	May 15	Oct 5	143
Quemado	—	Quemado	Jun 1	Sep 29	117
Questa	Costilla, Taos Ski Valley	Cerro	May 31	Sep 26	116
Raton	—	Raton Krtn Radio	May 19	Sep 29	132
Red River	—	Red River	Jun 19	Sep 7	77
Red Rock Ranch	—	Thoreau 12 Se	May 29	Sep 26	118
Reserve *	—	Reserve Rs	May 30	Oct 3	127
Sagar	Black Rock	Zuni	May 29	Oct 2	127
San Rafael	Milan, Bluewater	Grants Ap	May 17	Oct 3	137
Springer	—	Springer	Apr 30	Oct 11	164
Taos	Ranchos de Taos, Talpa	Taos	May 19	Oct 3	136
Thoreau	Borrego Pass, Continental Divide, McGaffey	Mcgaffey 5 Se	Jun 5	Sep 25	109
Truchas	Cundiyo, Picuris Pueblo	Alcalde	May 10	Oct 4	145
Ute Park	Springer	Cimarron 4 Sw	May 11	Oct 3	143
Wagon Mound	Watrous	Valmora	May 18	Oct 1	135

* Reserve 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 (Reserve, representative)

Computed from Reserve's average frost dates — the median-season location in this New Mexicozone 6a 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).

Crop

JanFebMarAprMayJunJulAugSepOctNovDec

Tomato

Pepper

Cucumber

Summer squash / zucchini

Start indoors
Plant out
Fall sowing
First harvest

Planting windows for Reserve (New Mexico, zone 6a), this group's representative location.
Crop	Frost tolerance	Start indoors	Plant out	First harvest	Fall planting	Season fit
Tomato	Tender	Apr 4 – Apr 18	Jun 6 – Jun 13	Aug 5 – Aug 25	—	matures comfortably
Pepper	Very tender	Mar 21 – Apr 4	Jun 13 – Jun 20	Aug 12 – Sep 11	—	matures comfortably
Cucumber	Tender	May 2 – May 9	Jun 6 – Jun 13	Jul 26 – Aug 15	—	matures comfortably
Summer squash / zucchini	Tender	—	Jun 6 – Jun 13	Jul 21 – Aug 5	—	matures comfortably
Bush bean	Tender	—	Jun 6 – Jun 13	Jul 26 – Aug 5	Aug 4 – Aug 14	matures comfortably
Sweet corn	Tender	—	May 30 – Jun 13	Jul 29 – Aug 28	—	matures comfortably
Basil	Very tender	Apr 18 – May 2	Jun 6 – Jun 13	Jul 6 – Jul 21	—	matures comfortably
Lettuce	Half-hardy	Apr 18 – May 2	May 2 – May 16	Jun 16 – Jul 1	Jul 21 – Aug 5	matures comfortably
Pea	Hardy	—	Apr 18 – May 2	Jun 12 – Jun 27	Jul 11 – Jul 26	matures comfortably
Spinach	Hardy	—	Apr 18 – May 2	May 28 – Jun 7	Jul 31 – Aug 10	matures comfortably
Carrot	Half-hardy	—	May 9 – May 16	Jul 8 – Jul 28	Jul 1 – Jul 21	matures comfortably
Broccoli	Half-hardy	Apr 4 – Apr 18	May 2 – May 16	Jun 26 – Jul 16	Jul 6 – Jul 26	matures comfortably

Which crops fit this growing season

Using Reserve's own 127-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 (Reserve)

From NOAA's 1991–2020 Climate Normals at station USC00297386. 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.

Freeze probabilities by temperature threshold (MM/DD, NOAA 1991–2020), Reserve.
Threshold	Last spring — avg	Last spring — 90%-safe	First fall — avg	First fall — 90%-safe	Season (days)
36°F	Jun 10	Jun 25	Sep 26	Oct 5	107
32°F (freeze)	May 30	Jun 12	Oct 3	Oct 14	127
28°F	May 13	Jun 2	Oct 12	Oct 25	150
24°F	May 1	May 13	Oct 23	Nov 5	173

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 29 locations is 2,289; Reserve's own reading is shown below.

Annual growing degree days for Reserve (°F·days, NOAA 1991–2020).
Model	°F·days	Used for
Base 50°F (warm-season)	2,877	standard warm-season base (tomato, corn, beans)
Base 40°F (cool-season)	5,394	cool-season crops (brassicas, greens)

Hardiness zone 6a in New Mexico

Zone 6a means an average annual extreme minimum winter temperature of about −10 to −5 °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, 6b, 7a, 7b, 8a, 8b.

Explore zone 6a in other states at zone 6a, or see all USDA hardiness zones.

Frequently asked questions

What does USDA hardiness zone 6a mean in New Mexico?: Zone 6a means an average annual extreme minimum winter temperature of −10 to −5 °F — the standard USDA measure of which perennials survive winter. 29 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 6a is the growing season longest?: Springer runs the longest season on this page at about 164 days; Red River is shortest at about 77 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 6a?: Using Reserve's frost dates (this page's median-season location): start seeds indoors about Apr 4 – Apr 18, then transplant outside about Jun 6 – Jun 13. 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 6a 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 29 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.