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

Planting zone for 81073 — Springfield, CO

ZIP code 81073 (Springfield, Baca County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 3 and the first fall frost October 10.

Where ZIP 81073 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostMay 3
First frostOct 10
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Springfield, 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 Springfield, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 3median — 50% chance of a later frost
Safe for tender plantsMay 17only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 29
Growing season158 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 24 and returns around October 19.

From the NOAA station Springfield Comanche, CO — 11 miles away, elevation 4,383 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 81073

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 22 – Apr 5
SpinachSow outdoors · Mar 22 – Apr 12
Broccoli, cabbageStart indoors · Feb 22 – Mar 8
Broccoli, cabbageTransplant · Apr 12 – Apr 26
Onion setsPlant outdoors · Apr 5 – Apr 19
PotatoesPlant outdoors · Apr 12 – Apr 26
LettuceSow outdoors · Apr 5 – Apr 19
Carrots, beetsSow outdoors · Apr 12 – Apr 26
TomatoesStart indoors · Mar 8 – Mar 22
TomatoesTransplant · May 10 – May 24
Peppers, eggplantStart indoors · Feb 22 – Mar 8
Peppers, eggplantTransplant · May 17 – May 31
BeansSow outdoors · May 10 – May 24
Sweet cornSow outdoors · May 10 – May 24
Cucumbers, squashSow outdoors · May 10 – May 24
Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 10) 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 81073 came on Feb 20 — 19 days earlier than the 1991–2020 average (Mar 11).

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 6b in Colorado

565 plants native to the lower 48 states, recorded in Colorado, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 28

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 104

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 252

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 168

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 4

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Springfield, CO.

Soil in Springfield, CO

The soil mapped at the center of ZIP 81073 is Wiley — loam, well drained.

TextureLoama good balance for most vegetables
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Wiley loam, 1 to 3 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 81073; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Springfield, CO

Summer high91 °Faverage high, July
Winter low17 °Faverage low, January
Hot days66days a year at 90 °F or more
Freezing nights150nights a year at 32 °F or less
Growing degree days3,343base 50 °F — the season’s usable heat
Longest day14 h 45 mindaylight on June 21
Shortest day9 h 35 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation15.9 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 48 °F, low 17 °F 48°17° JanFebruary: average high 50 °F, low 19 °F 50°19° FebMarch: average high 59 °F, low 27 °F 59°27° MarApril: average high 66 °F, low 34 °F 66°34° AprMay: average high 76 °F, low 45 °F 76°45° MayJune: average high 87 °F, low 55 °F 87°55° JunJuly: average high 91 °F, low 61 °F 91°61° JulAugust: average high 88 °F, low 59 °F 88°59° AugSeptember: average high 81 °F, low 51 °F 81°51° SepOctober: average high 69 °F, low 37 °F 69°37° OctNovember: average high 57 °F, low 25 °F 57°25° NovDecember: average high 47 °F, low 18 °F 47°18° Dec

Precipitation by month inches

0″1″2″3″January: 0.37 in precipitation 0.4 JanFebruary: 0.27 in precipitation 0.3 FebMarch: 0.82 in precipitation 0.8 MarApril: 1.40 in precipitation 1.4 AprMay: 1.76 in precipitation 1.8 MayJune: 2.16 in precipitation 2.2 JunJuly: 3.00 in precipitation 3.0 JulAugust: 2.72 in precipitation 2.7 AugSeptember: 1.40 in precipitation 1.4 SepOctober: 1.10 in precipitation 1.1 OctNovember: 0.43 in precipitation 0.4 NovDecember: 0.49 in precipitation 0.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Springfield Comanche, CO (11 mi away); precipitation: Springfield 0.5 Nw, CO (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

810876b
Vilas, CO · 16 mi
810846b
Two Buttes, CO · 18 mi
810646b
Pritchett, CO · 21 mi
810296b
Campo, CO · 26 mi
810906b
Walsh, CO · 26 mi
810446a
Hasty, CO · 33 mi
810416a
Granada, CO · 34 mi
739466b
Kenton, OK · 34 mi

Colorado planting zones →

Questions about 81073

What planting zone is ZIP code 81073?

ZIP code 81073 (Springfield, CO) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Springfield, CO?

The median last spring frost (32 °F) near 81073 is May 3; after May 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Springfield Comanche station.

When is the first frost in Springfield, CO?

The median first fall frost near 81073 is October 10, giving a median frost-free growing season of 158 days.

When should I plant tomatoes in 81073?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 81073 get?

About 15.9 inches of precipitation a year (NOAA 1991–2020 normals, Springfield 0.5 Nw station).

How hot do summers get in Springfield, CO?

The average high peaks at 91 °F in July, with about 66 days a year at 90 °F or more.

What kind of soil does 81073 have?

The USDA soil survey maps Wiley at the center of ZIP 81073: loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Springfield, CO in 2026?

Spring leaf-out near 81073 came on Feb 20 in 2026, 19 days earlier than the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Springfield, CO?

Intermediate onions: the longest day near 81073 is 14 h 45 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81073 change?

Yes. The 2012 USDA map put 81073 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.