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

Planting zone for 80427 — Central City, CO

ZIP code 80427 (Central City, Gilpin County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is June 5 and the first fall frost September 16.

Where ZIP 80427 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 5

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 Central City, 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 Central City, CO

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostJune 5median — 50% chance of a later frost

Safe for tender plantsJune 19only 10% chance of frost after

First fall frostSeptember 16median — 10% chance by Sep 2

Growing season103 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 21 and returns around September 26.

From the NOAA station Coal Creek Canyon, CO — 10 miles away, elevation 8,951 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 80427

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 24 – May 8

SpinachSow outdoors · Apr 24 – May 15

Broccoli, cabbageStart indoors · Mar 27 – Apr 10

Broccoli, cabbageTransplant · May 15 – May 29

Onion setsPlant outdoors · May 8 – May 22

PotatoesPlant outdoors · May 15 – May 29

LettuceSow outdoors · May 8 – May 22

Carrots, beetsSow outdoors · May 15 – May 29

TomatoesStart indoors · Apr 10 – Apr 24

TomatoesTransplant · Jun 12 – Jun 26

Peppers, eggplantStart indoors · Mar 27 – Apr 10

Peppers, eggplantTransplant · Jun 19 – Jul 3

BeansSow outdoors · Jun 12 – Jun 26

Sweet cornSow outdoors · Jun 12 – Jun 26

Cucumbers, squashSow outdoors · Jun 12 – Jun 26

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 5) 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 80427 came on Apr 1 — 34 days earlier than the 1991–2020 average (May 5).

average
May 52026
Apr 1

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.

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 Central City, CO.

Soil in Central City, CO

The soil mapped at the center of ZIP 80427 is Resort — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Resort-Cathedral complex, 30 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 80427; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Central City, CO

Summer high73 °Faverage high, July

Winter low15 °Faverage low, February

Hot days0days a year at 90 °F or more

Freezing nights211nights a year at 32 °F or less

Growing degree days917base 50 °F — the season’s usable heat

Longest day15 h 00 mindaylight on June 21

Shortest day9 h 21 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation19.3 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: Coal Creek Canyon, CO (10 mi away); precipitation: Golden 9.4 Wnw, CO (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

804225b

Black Hawk, CO · 5 mi

804365b

Dumont, CO · 6 mi

804525b

Idaho Springs, CO · 7 mi

804745b

Rollinsville, CO · 9 mi

804715b

Pinecliffe, CO · 11 mi

804035b

Golden, CO · 11 mi

804395b

Evergreen, CO · 12 mi

804665b

Nederland, CO · 13 mi

Colorado planting zones →

Questions about 80427

What planting zone is ZIP code 80427?

ZIP code 80427 (Central City, 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 Central City, CO?

The median last spring frost (32 °F) near 80427 is June 5; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Coal Creek Canyon station.

When is the first frost in Central City, CO?

The median first fall frost near 80427 is September 16, giving a median frost-free growing season of 103 days.

When should I plant tomatoes in 80427?

Start tomato seeds indoors around Apr 10 – Apr 24 and set transplants outside around Jun 12 – Jun 26, one to three weeks after the median last frost.

How much rain and snow does 80427 get?

About 19.3 inches of precipitation a year (NOAA 1991–2020 normals, Golden 9.4 Wnw station).

How hot do summers get in Central City, CO?

The average high peaks at 73 °F in July, with about 0 days a year at 90 °F or more.

What kind of soil does 80427 have?

The USDA soil survey maps Resort at the center of ZIP 80427: slightly decomposed plant material, somewhat excessively drained, pH about 5.8 (moderately acidic).

Did spring come early in Central City, CO in 2026?

Spring leaf-out near 80427 came on Apr 1 in 2026, 34 days earlier than the 1991–2020 average (May 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Central City, CO?

Intermediate onions: the longest day near 80427 is 15 h 00 min, so day-neutral types bulb best; long-day varieties may not bulb fully.