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

Planting zone for 80452 — Idaho Springs, CO

ZIP code 80452 (Idaho Springs, Clear Creek County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 30 and the first fall frost September 19.

Where ZIP 80452 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 frostMay 30

First frostSep 19

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 Idaho Springs, 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 Idaho Springs, CO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 30median — 50% chance of a later frost

Safe for tender plantsJune 14only 10% chance of frost after

First fall frostSeptember 19median — 10% chance by Sep 5

Growing season112 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 15 and returns around September 30.

From the NOAA station Georgetown, CO — 6 miles away, elevation 8,521 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 80452

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 18 – May 2

SpinachSow outdoors · Apr 18 – May 9

Broccoli, cabbageStart indoors · Mar 21 – Apr 4

Broccoli, cabbageTransplant · May 9 – May 23

Onion setsPlant outdoors · May 2 – May 16

PotatoesPlant outdoors · May 9 – May 23

LettuceSow outdoors · May 2 – May 16

Carrots, beetsSow outdoors · May 9 – May 23

TomatoesStart indoors · Apr 4 – Apr 18

TomatoesTransplant · Jun 6 – Jun 20

Peppers, eggplantStart indoors · Mar 21 – Apr 4

Peppers, eggplantTransplant · Jun 13 – Jun 27

BeansSow outdoors · Jun 6 – Jun 20

Sweet cornSow outdoors · Jun 6 – Jun 20

Cucumbers, squashSow outdoors · Jun 6 – Jun 20

Fall lettuce, spinachSow outdoors · Jul 25 – Aug 8

GarlicPlant cloves · Sep 5 – Oct 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 30) and first fall frost (Sep 19) 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 80452 came on Mar 28 — 37 days earlier than the 1991–2020 average (May 4).

average
May 42026
Mar 28

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 Idaho Springs, CO.

Soil in Idaho Springs, CO

The soil mapped at the center of ZIP 80452 is Cathedral family — slightly decomposed plant material, somewhat excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.6moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter85%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Cathedral family-Rock outcrop complex, 40 to 150 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 80452; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Idaho Springs, CO

Summer high77 °Faverage high, July

Winter low15 °Faverage low, February

Hot days0days a year at 90 °F or more

Freezing nights210nights a year at 32 °F or less

Growing degree days1,197base 50 °F — the season’s usable heat

Longest day14 h 59 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

Precipitation26.7 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: Georgetown, CO (6 mi away); precipitation: Echo Lake, 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.

804365b

Dumont, CO · 5 mi

804275b

Central City, CO · 7 mi

804445a

Georgetown, CO · 9 mi

804395b

Evergreen, CO · 10 mi

804225b

Black Hawk, CO · 11 mi

804385a

Empire, CO · 11 mi

804765a

Silver Plume, CO · 13 mi

804745b

Rollinsville, CO · 15 mi

Colorado planting zones →

Questions about 80452

What planting zone is ZIP code 80452?

ZIP code 80452 (Idaho Springs, 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 Idaho Springs, CO?

The median last spring frost (32 °F) near 80452 is May 30; after June 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Georgetown station.

When is the first frost in Idaho Springs, CO?

The median first fall frost near 80452 is September 19, giving a median frost-free growing season of 112 days.

When should I plant tomatoes in 80452?

Start tomato seeds indoors around Apr 4 – Apr 18 and set transplants outside around Jun 6 – Jun 20, one to three weeks after the median last frost.

How much rain and snow does 80452 get?

About 26.7 inches of precipitation a year (NOAA 1991–2020 normals, Echo Lake station).

How hot do summers get in Idaho Springs, 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 80452 have?

The USDA soil survey maps Cathedral family at the center of ZIP 80452: slightly decomposed plant material, somewhat excessively drained, pH about 5.6 (moderately acidic).

Did spring come early in Idaho Springs, CO in 2026?

Spring leaf-out near 80452 came on Mar 28 in 2026, 37 days earlier than the 1991–2020 average (May 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Idaho Springs, CO?

Intermediate onions: the longest day near 80452 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 80452 change?

Yes. The 2012 USDA map put 80452 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.