Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 81128 — Chromo, CO

ZIP code 81128 (Chromo, Archuleta County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is June 14 and the first fall frost September 18.

Where ZIP 81128 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostJun 14
First frostSep 18
2012 zone5a

Was 5a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Chromo, CO…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Chromo, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 14median — 50% chance of a later frost
Safe for tender plantsJune 30only 10% chance of frost after
First fall frostSeptember 18median — 10% chance by Sep 7
Growing season93 daysfrost-free, median

A hard freeze (28 °F) usually ends around June 1 and returns around September 26.

From the NOAA station Chama, NM — 11 miles away, elevation 7,851 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 81128

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · May 3 – May 17
SpinachSow outdoors · May 3 – May 24
Broccoli, cabbageStart indoors · Apr 5 – Apr 19
Broccoli, cabbageTransplant · May 24 – Jun 7
Onion setsPlant outdoors · May 17 – May 31
PotatoesPlant outdoors · May 24 – Jun 7
LettuceSow outdoors · May 17 – May 31
Carrots, beetsSow outdoors · May 24 – Jun 7
TomatoesStart indoors · Apr 19 – May 3
TomatoesTransplant · Jun 21 – Jul 5
Peppers, eggplantStart indoors · Apr 5 – Apr 19
Peppers, eggplantTransplant · Jun 28 – Jul 12
BeansSow outdoors · Jun 21 – Jul 5
Sweet cornSow outdoors · Jun 21 – Jul 5
Cucumbers, squashSow outdoors · Jun 21 – Jul 5
Fall lettuce, spinachSow outdoors · Jul 24 – Aug 7
GarlicPlant cloves · Sep 4 – Oct 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 14) and first fall frost (Sep 18) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 81128 came on May 14 — 8 days earlier than the 1991–2020 average (May 22).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 5b in Colorado

546 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 27

American elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblack walnut100 ft · blooms late spring · high shade tolerance · to −28 °Fblack willow100 ft · blooms early spring · high shade tolerance · to −58 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °F

Shrubs 98

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FApache plume6 ft · blooms late spring · high shade tolerance · to −23 °F

Wildflowers & perennials 246

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine aster0.3 ft · blooms early summer · medium shade tolerance · to −28 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °F

Grasses 163

Alaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAlpine Meadow-Foxtail0.5 ft · blooms mid spring · medium shade tolerance · to −33 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Chromo, CO.

Soil in Chromo, CO

The soil mapped at the center of ZIP 81128 is Leighcan — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
pH5.6moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter85%high
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Leighcan-Frisco association, moist, 5 to 60 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 81128; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Chromo, CO

Summer high80 °Faverage high, July
Winter low7 °Faverage low, January
Hot days2days a year at 90 °F or more
Freezing nights231nights a year at 32 °F or less
Growing degree days1,239base 50 °F — the season’s usable heat
Longest day14 h 43 mindaylight on June 21
Shortest day9 h 37 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation21.1 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 38 °F, low 7 °F 38°7° JanFebruary: average high 41 °F, low 11 °F 41°11° FebMarch: average high 48 °F, low 18 °F 48°18° MarApril: average high 56 °F, low 24 °F 56°24° AprMay: average high 66 °F, low 32 °F 66°32° MayJune: average high 77 °F, low 39 °F 77°39° JunJuly: average high 80 °F, low 46 °F 80°46° JulAugust: average high 78 °F, low 46 °F 78°46° AugSeptember: average high 72 °F, low 38 °F 72°38° SepOctober: average high 61 °F, low 27 °F 61°27° OctNovember: average high 48 °F, low 17 °F 48°17° NovDecember: average high 38 °F, low 8 °F 38°8° Dec

Precipitation by month inches

0″1″2″3″January: 2.42 in precipitation 2.4 JanFebruary: 2.23 in precipitation 2.2 FebMarch: 1.80 in precipitation 1.8 MarApril: 1.59 in precipitation 1.6 AprMay: 1.52 in precipitation 1.5 MayJune: 0.55 in precipitation 0.6 JunJuly: 1.62 in precipitation 1.6 JulAugust: 2.04 in precipitation 2.0 AugSeptember: 1.75 in precipitation 1.8 SepOctober: 1.64 in precipitation 1.6 OctNovember: 1.83 in precipitation 1.8 NovDecember: 2.16 in precipitation 2.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Chama, NM (11 mi away); precipitation: Chamita, NM (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

875205b
Chama, NM · 14 mi
811205b
Antonito, CO · 17 mi
875285b
Dulce, NM · 25 mi
811575b
Pagosa Springs, CO · 25 mi
875515b
Los Ojos, NM · 26 mi
811475b
Pagosa Springs, CO · 29 mi
811405b
La Jara, CO · 29 mi
875755b
Tierra Amarilla, NM · 30 mi

Colorado planting zones →

Questions about 81128

What planting zone is ZIP code 81128?

ZIP code 81128 (Chromo, CO) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Chromo, CO?

The median last spring frost (32 °F) near 81128 is June 14; after June 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Chama station.

When is the first frost in Chromo, CO?

The median first fall frost near 81128 is September 18, giving a median frost-free growing season of 93 days.

When should I plant tomatoes in 81128?

Start tomato seeds indoors around Apr 19 – May 3 and set transplants outside around Jun 21 – Jul 5, one to three weeks after the median last frost.

How much rain and snow does 81128 get?

About 21.1 inches of precipitation a year (NOAA 1991–2020 normals, Chamita station).

How hot do summers get in Chromo, CO?

The average high peaks at 80 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 81128 have?

The USDA soil survey maps Leighcan at the center of ZIP 81128: moderately decomposed plant material, well drained, pH about 5.6 (moderately acidic).

Did spring come early in Chromo, CO in 2026?

Spring leaf-out near 81128 came on May 14 in 2026, 8 days earlier than the 1991–2020 average (May 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Chromo, CO?

Intermediate onions: the longest day near 81128 is 14 h 43 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81128 change?

Yes. The 2012 USDA map put 81128 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.