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

Planting zone for 80820 — Guffey, CO

ZIP code 80820 (Guffey, Park County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is June 2 and the first fall frost September 19.

Where ZIP 80820 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 2
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 Guffey, 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 Guffey, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 2median — 50% chance of a later frost
Safe for tender plantsJune 17only 10% chance of frost after
First fall frostSeptember 19median — 10% chance by Sep 6
Growing season108 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 19 and returns around September 29.

From the NOAA station Lake George 8 Sw, CO — 11 miles away, elevation 8,550 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 80820

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 21 – May 5
SpinachSow outdoors · Apr 21 – May 12
Broccoli, cabbageStart indoors · Mar 24 – Apr 7
Broccoli, cabbageTransplant · May 12 – May 26
Onion setsPlant outdoors · May 5 – May 19
PotatoesPlant outdoors · May 12 – May 26
LettuceSow outdoors · May 5 – May 19
Carrots, beetsSow outdoors · May 12 – May 26
TomatoesStart indoors · Apr 7 – Apr 21
TomatoesTransplant · Jun 9 – Jun 23
Peppers, eggplantStart indoors · Mar 24 – Apr 7
Peppers, eggplantTransplant · Jun 16 – Jun 30
BeansSow outdoors · Jun 9 – Jun 23
Sweet cornSow outdoors · Jun 9 – Jun 23
Cucumbers, squashSow outdoors · Jun 9 – Jun 23
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 (Jun 2) 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 80820 came on Apr 1 — 34 days earlier than the 1991–2020 average (May 5).

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.

Trees 27

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 98

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 246

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 163

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 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Guffey, CO.

Soil in Guffey, CO

The soil mapped at the center of ZIP 80820 is Adderton — loam, well drained.

TextureLoama good balance for most vegetables
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Adderton-Bushpark complex, 2 to 40 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 80820; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Guffey, CO

Summer high77 °Faverage high, July
Winter low−1 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights228nights a year at 32 °F or less
Growing degree days1,044base 50 °F — the season’s usable heat
Longest day14 h 53 mindaylight on June 21
Shortest day9 h 27 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation16.1 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 33 °F, low -1 °F 33°−1° JanFebruary: average high 36 °F, low 3 °F 36°3° FebMarch: average high 45 °F, low 13 °F 45°13° MarApril: average high 51 °F, low 23 °F 51°23° AprMay: average high 61 °F, low 32 °F 61°32° MayJune: average high 72 °F, low 41 °F 72°41° JunJuly: average high 77 °F, low 46 °F 77°46° JulAugust: average high 75 °F, low 45 °F 75°45° AugSeptember: average high 69 °F, low 37 °F 69°37° SepOctober: average high 57 °F, low 26 °F 57°26° OctNovember: average high 45 °F, low 15 °F 45°15° NovDecember: average high 34 °F, low 2 °F 34°2° Dec

Precipitation by month inches

0″1″2″3″January: 0.86 in precipitation 0.9 JanFebruary: 0.75 in precipitation 0.8 FebMarch: 0.91 in precipitation 0.9 MarApril: 1.54 in precipitation 1.5 AprMay: 1.60 in precipitation 1.6 MayJune: 0.93 in precipitation 0.9 JunJuly: 2.80 in precipitation 2.8 JulAugust: 2.92 in precipitation 2.9 AugSeptember: 1.44 in precipitation 1.4 SepOctober: 0.99 in precipitation 1.0 OctNovember: 0.73 in precipitation 0.7 NovDecember: 0.67 in precipitation 0.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lake George 8 Sw, CO (11 mi away); precipitation: Guffey 5.5 W, CO (4 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.

808165a
Florissant, CO · 15 mi
804494a
Hartsel, CO · 16 mi
812126a
Canon City, CO · 18 mi
808275b
Lake George, CO · 20 mi
812156a
Canon City, CO · 21 mi
808145b
Divide, CO · 23 mi
812335b
Howard, CO · 24 mi
808135b
Cripple Creek, CO · 24 mi

Colorado planting zones →

Questions about 80820

What planting zone is ZIP code 80820?

ZIP code 80820 (Guffey, 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 Guffey, CO?

The median last spring frost (32 °F) near 80820 is June 2; after June 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lake George 8 Sw station.

When is the first frost in Guffey, CO?

The median first fall frost near 80820 is September 19, giving a median frost-free growing season of 108 days.

When should I plant tomatoes in 80820?

Start tomato seeds indoors around Apr 7 – Apr 21 and set transplants outside around Jun 9 – Jun 23, one to three weeks after the median last frost.

How much rain and snow does 80820 get?

About 16.1 inches of precipitation a year (NOAA 1991–2020 normals, Guffey 5.5 W station).

How hot do summers get in Guffey, 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 80820 have?

The USDA soil survey maps Adderton at the center of ZIP 80820: loam, well drained, pH about 7.2 (neutral).

Did spring come early in Guffey, CO in 2026?

Spring leaf-out near 80820 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 Guffey, CO?

Intermediate onions: the longest day near 80820 is 14 h 53 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 80820 change?

Yes. The 2012 USDA map put 80820 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.