Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 80430 — Coalmont, CO

ZIP code 80430 (Coalmont, Jackson County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is June 9 and the first fall frost September 12.

Where ZIP 80430 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.

Zone4b−25 to −20 °F

Coldest night−31.7 to −28.9 °C

Last frostJun 9

First frostSep 12

2012 zone4b

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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Coalmont, 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 Coalmont, 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 12median — 10% chance by Aug 31

Growing season93 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around September 23.

From the NOAA station Steamboat Springs, CO — 22 miles away, elevation 6,867 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 80430

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 18 – Aug 1

GarlicPlant cloves · Aug 29 – Oct 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 9) and first fall frost (Sep 12) 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 80430 came on Apr 23 — 15 days earlier than the 1991–2020 average (May 8).

average
May 82026
Apr 23

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 4b in Colorado

484 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

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 Coalmont, CO.

Soil in Coalmont, CO

The soil mapped at the center of ZIP 80430 is Cabin — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

pH7.0neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Cabin sandy loam.

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 80430; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Coalmont, CO

Summer high77 °Faverage high, July

Winter low7 °Faverage low, January

Hot days0days a year at 90 °F or more

Freezing nights253nights a year at 32 °F or less

Growing degree days794base 50 °F — the season’s usable heat

Longest day15 h 04 mindaylight on June 21

Shortest day9 h 16 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation15.2 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Spicer, CO (4 mi away); precipitation: Spicer, CO (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Steamboat Springs, CO · 22 mi

804884b

Steamboat Springs, CO · 24 mi

804875b

Steamboat Springs, CO · 25 mi

804595a

Kremmling, CO · 25 mi

Colorado planting zones →

Questions about 80430

What planting zone is ZIP code 80430?

ZIP code 80430 (Coalmont, CO) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Coalmont, CO?

The median last spring frost (32 °F) near 80430 is June 9; after June 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Steamboat Springs station.

When is the first frost in Coalmont, CO?

The median first fall frost near 80430 is September 12, giving a median frost-free growing season of 93 days.

When should I plant tomatoes in 80430?

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 80430 get?

About 15.2 inches of precipitation a year (NOAA 1991–2020 normals, Spicer station).

How hot do summers get in Coalmont, CO?

The average high peaks at 77 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 80430 have?

The USDA soil survey maps Cabin at the center of ZIP 80430: sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Coalmont, CO in 2026?

Spring leaf-out near 80430 came on Apr 23 in 2026, 15 days earlier than the 1991–2020 average (May 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Coalmont, CO?

Long-day onions: the longest day near 80430 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).