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

Planting zone for 81243 — Powderhorn, CO

ZIP code 81243 (Powderhorn, Gunnison County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is June 9 and the first fall frost September 16.

Where ZIP 81243 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 9
First frostSep 16
2012 zone5b

Same zone as on the 2012 map. 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 Powderhorn, 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 Powderhorn, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 9median — 50% chance of a later frost
Safe for tender plantsJune 24only 10% chance of frost after
First fall frostSeptember 16median — 10% chance by Sep 3
Growing season96 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 25 and returns around September 27.

From the NOAA station Blue Mesa Lake, CO — 14 miles away, elevation 7,569 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 81243

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 28 – May 12
SpinachSow outdoors · Apr 28 – May 19
Broccoli, cabbageStart indoors · Mar 31 – Apr 14
Broccoli, cabbageTransplant · May 19 – Jun 2
Onion setsPlant outdoors · May 12 – May 26
PotatoesPlant outdoors · May 19 – Jun 2
LettuceSow outdoors · May 12 – May 26
Carrots, beetsSow outdoors · May 19 – Jun 2
TomatoesStart indoors · Apr 14 – Apr 28
TomatoesTransplant · Jun 16 – Jun 30
Peppers, eggplantStart indoors · Mar 31 – Apr 14
Peppers, eggplantTransplant · Jun 23 – Jul 7
BeansSow outdoors · Jun 16 – Jun 30
Sweet cornSow outdoors · Jun 16 – Jun 30
Cucumbers, squashSow outdoors · Jun 16 – Jun 30
Fall lettuce, spinachSow outdoors · Jul 22 – Aug 5
GarlicPlant cloves · Sep 2 – Oct 7
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 9) and first fall frost (Sep 16) 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 81243 came on Mar 31 — 30 days earlier than the 1991–2020 average (Apr 30).

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 Powderhorn, CO.

Soil in Powderhorn, CO

The soil mapped at the center of ZIP 81243 is Posant — slightly decomposed plant material, well drained.

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

Map unit: Posant very rocky loam, 10 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 81243; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Powderhorn, CO

Summer high83 °Faverage high, July
Winter low−1 °Faverage low, January
Hot days5days a year at 90 °F or more
Freezing nights220nights a year at 32 °F or less
Growing degree days1,327base 50 °F — the season’s usable heat
Longest day14 h 50 mindaylight on June 21
Shortest day9 h 30 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation17.1 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 26 °F, low -1 °F 26°−1° JanFebruary: average high 31 °F, low 3 °F 31°3° FebMarch: average high 44 °F, low 15 °F 44°15° 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 83 °F, low 46 °F 83°46° JulAugust: average high 80 °F, low 45 °F 80°45° AugSeptember: average high 73 °F, low 37 °F 73°37° SepOctober: average high 60 °F, low 27 °F 60°27° OctNovember: average high 44 °F, low 16 °F 44°16° NovDecember: average high 29 °F, low 3 °F 29°3° Dec

Precipitation by month inches

0″1″2″January: 1.28 in precipitation 1.3 JanFebruary: 1.34 in precipitation 1.3 FebMarch: 1.24 in precipitation 1.2 MarApril: 1.65 in precipitation 1.6 AprMay: 1.15 in precipitation 1.1 MayJune: 0.73 in precipitation 0.7 JunJuly: 1.74 in precipitation 1.7 JulAugust: 1.76 in precipitation 1.8 AugSeptember: 1.87 in precipitation 1.9 SepOctober: 1.43 in precipitation 1.4 OctNovember: 1.44 in precipitation 1.4 NovDecember: 1.45 in precipitation 1.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Blue Mesa Lake, CO (14 mi away); precipitation: Powderhorn 4.4 Nne, CO (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

812205b
Cimarron, CO · 16 mi
812305b
Gunnison, CO · 16 mi
812355a
Lake City, CO · 24 mi
814275b
Ouray, CO · 28 mi
814326a
Ridgway, CO · 31 mi
814156a
Crawford, CO · 34 mi
812394b
Parlin, CO · 37 mi
812485b
Sargents, CO · 39 mi

Colorado planting zones →

Questions about 81243

What planting zone is ZIP code 81243?

ZIP code 81243 (Powderhorn, 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 Powderhorn, CO?

The median last spring frost (32 °F) near 81243 is June 9; after June 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Blue Mesa Lake station.

When is the first frost in Powderhorn, CO?

The median first fall frost near 81243 is September 16, giving a median frost-free growing season of 96 days.

When should I plant tomatoes in 81243?

Start tomato seeds indoors around Apr 14 – Apr 28 and set transplants outside around Jun 16 – Jun 30, one to three weeks after the median last frost.

How much rain and snow does 81243 get?

About 17.1 inches of precipitation a year (NOAA 1991–2020 normals, Powderhorn 4.4 Nne station).

How hot do summers get in Powderhorn, CO?

The average high peaks at 83 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 81243 have?

The USDA soil survey maps Posant at the center of ZIP 81243: slightly decomposed plant material, well drained, pH about 5.6 (moderately acidic).

Did spring come early in Powderhorn, CO in 2026?

Spring leaf-out near 81243 came on Mar 31 in 2026, 30 days earlier than the 1991–2020 average (Apr 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Powderhorn, CO?

Intermediate onions: the longest day near 81243 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.