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

Planting zone for 81227 — Monarch, CO

ZIP code 81227 (Monarch, Chaffee County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 29 and the first fall frost September 20.

Where ZIP 81227 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 29

First frostSep 20

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 Monarch, 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 Monarch, CO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 29median — 50% chance of a later frost

Safe for tender plantsJune 12only 10% chance of frost after

First fall frostSeptember 20median — 10% chance by Sep 8

Growing season112 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 17 and returns around September 29.

From the NOAA station Salida, CO — 15 miles away, elevation 7,159 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 81227

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 17 – May 1

SpinachSow outdoors · Apr 17 – May 8

Broccoli, cabbageStart indoors · Mar 20 – Apr 3

Broccoli, cabbageTransplant · May 8 – May 22

Onion setsPlant outdoors · May 1 – May 15

PotatoesPlant outdoors · May 8 – May 22

LettuceSow outdoors · May 1 – May 15

Carrots, beetsSow outdoors · May 8 – May 22

TomatoesStart indoors · Apr 3 – Apr 17

TomatoesTransplant · Jun 5 – Jun 19

Peppers, eggplantStart indoors · Mar 20 – Apr 3

Peppers, eggplantTransplant · Jun 12 – Jun 26

BeansSow outdoors · Jun 5 – Jun 19

Sweet cornSow outdoors · Jun 5 – Jun 19

Cucumbers, squashSow outdoors · Jun 5 – Jun 19

Fall lettuce, spinachSow outdoors · Jul 26 – Aug 9

GarlicPlant cloves · Sep 6 – Oct 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 29) and first fall frost (Sep 20) 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 81227 came on May 8 — 11 days earlier than the 1991–2020 average (May 19).

average
May 192026
May 8

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 Monarch, CO.

Soil in Monarch, CO

The soil mapped at the center of ZIP 81227 is Howardsville family — slightly decomposed plant material, excessively drained.

TextureSlightly decomposed plant materialtop layer

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageExcessively drainednatural drainage class

Organic matter75%high

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Howardsville family, 15 to 25 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 81227; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Monarch, CO

Summer high82 °Faverage high, July

Winter low−5 °Faverage low, January

Hot days4days a year at 90 °F or more

Freezing nights295nights a year at 32 °F or less

Growing degree days782base 50 °F — the season’s usable heat

Longest day14 h 52 mindaylight on June 21

Shortest day9 h 28 mindaylight on December 21

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

Precipitation26 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: Sargents, CO (12 mi away); precipitation: Porphyry Creek, CO (5 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.

Poncha Springs, CO · 13 mi

Ohio City, CO · 18 mi

811555b

Villa Grove, CO · 22 mi

Colorado planting zones →

Questions about 81227

What planting zone is ZIP code 81227?

ZIP code 81227 (Monarch, 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 Monarch, CO?

The median last spring frost (32 °F) near 81227 is May 29; after June 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Salida station.

When is the first frost in Monarch, CO?

The median first fall frost near 81227 is September 20, giving a median frost-free growing season of 112 days.

When should I plant tomatoes in 81227?

Start tomato seeds indoors around Apr 3 – Apr 17 and set transplants outside around Jun 5 – Jun 19, one to three weeks after the median last frost.

How much rain and snow does 81227 get?

About 26 inches of precipitation a year (NOAA 1991–2020 normals, Porphyry Creek station).

How hot do summers get in Monarch, CO?

The average high peaks at 82 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 81227 have?

The USDA soil survey maps Howardsville family at the center of ZIP 81227: slightly decomposed plant material, excessively drained, pH about 5.0 (strongly acidic).

Did spring come early in Monarch, CO in 2026?

Spring leaf-out near 81227 came on May 8 in 2026, 11 days earlier than the 1991–2020 average (May 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Monarch, CO?

Intermediate onions: the longest day near 81227 is 14 h 52 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81227 change?

Yes. The 2012 USDA map put 81227 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.