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

Planting zone for 81637 — Gypsum, CO

ZIP code 81637 (Gypsum, Eagle County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 1 and the first fall frost October 14.

Where ZIP 81637 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 1
First frostOct 14
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 Gypsum, 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 Gypsum, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 1median — 50% chance of a later frost
Safe for tender plantsMay 14only 10% chance of frost after
First fall frostOctober 14median — 10% chance by Oct 1
Growing season164 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 23.

From the NOAA station Shoshone, CO — 16 miles away, elevation 5,991 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 81637

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 20 – Apr 3
SpinachSow outdoors · Mar 20 – Apr 10
Broccoli, cabbageStart indoors · Feb 20 – Mar 6
Broccoli, cabbageTransplant · Apr 10 – Apr 24
Onion setsPlant outdoors · Apr 3 – Apr 17
PotatoesPlant outdoors · Apr 10 – Apr 24
LettuceSow outdoors · Apr 3 – Apr 17
Carrots, beetsSow outdoors · Apr 10 – Apr 24
TomatoesStart indoors · Mar 6 – Mar 20
TomatoesTransplant · May 8 – May 22
Peppers, eggplantStart indoors · Feb 20 – Mar 6
Peppers, eggplantTransplant · May 15 – May 29
BeansSow outdoors · May 8 – May 22
Sweet cornSow outdoors · May 8 – May 22
Cucumbers, squashSow outdoors · May 8 – May 22
Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2
GarlicPlant cloves · Sep 30 – Nov 4
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 14) 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 81637 came on Mar 31 — 25 days earlier than the 1991–2020 average (Apr 25).

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 Gypsum, CO.

Soil in Gypsum, CO

The soil mapped at the center of ZIP 81637 is Torriorthents — variable, well drained.

TextureVariabletop layer
pH7.3neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Torriorthents-Camborthids-Rock outcrop complex, 6 to 65 percent.

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 81637; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Gypsum, CO

Summer high89 °Faverage high, July
Winter low15 °Faverage low, January
Hot days44days a year at 90 °F or more
Freezing nights143nights a year at 32 °F or less
Growing degree days2,846base 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
Precipitation41.6 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 36 °F, low 15 °F 36°15° JanFebruary: average high 43 °F, low 20 °F 43°20° FebMarch: average high 53 °F, low 28 °F 53°28° MarApril: average high 62 °F, low 35 °F 62°35° AprMay: average high 71 °F, low 44 °F 71°44° MayJune: average high 83 °F, low 51 °F 83°51° JunJuly: average high 89 °F, low 59 °F 89°59° JulAugust: average high 87 °F, low 58 °F 87°58° AugSeptember: average high 79 °F, low 50 °F 79°50° SepOctober: average high 65 °F, low 38 °F 65°38° OctNovember: average high 49 °F, low 27 °F 49°27° NovDecember: average high 36 °F, low 16 °F 36°16° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 4.82 in precipitation 4.8 JanFebruary: 4.53 in precipitation 4.5 FebMarch: 4.16 in precipitation 4.2 MarApril: 4.69 in precipitation 4.7 AprMay: 3.34 in precipitation 3.3 MayJune: 1.58 in precipitation 1.6 JunJuly: 1.78 in precipitation 1.8 JulAugust: 2.12 in precipitation 2.1 AugSeptember: 2.70 in precipitation 2.7 SepOctober: 3.30 in precipitation 3.3 OctNovember: 3.89 in precipitation 3.9 NovDecember: 4.72 in precipitation 4.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Shoshone, CO (16 mi away); precipitation: Bison Lake, CO (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

804265b
Burns, CO · 9 mi
816016a
Glenwood Springs, CO · 18 mi
816026a
Glenwood Springs, CO · 20 mi
804795a
Toponas, CO · 20 mi
816315b
Eagle, CO · 21 mi
804635b
Mc Coy, CO · 23 mi
804835a
Yampa, CO · 23 mi
804695a
Phippsburg, CO · 31 mi

Colorado planting zones →

Questions about 81637

What planting zone is ZIP code 81637?

ZIP code 81637 (Gypsum, 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 Gypsum, CO?

The median last spring frost (32 °F) near 81637 is May 1; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Shoshone station.

When is the first frost in Gypsum, CO?

The median first fall frost near 81637 is October 14, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 81637?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 81637 get?

About 41.6 inches of precipitation a year (NOAA 1991–2020 normals, Bison Lake station).

How hot do summers get in Gypsum, CO?

The average high peaks at 89 °F in July, with about 44 days a year at 90 °F or more.

What kind of soil does 81637 have?

The USDA soil survey maps Torriorthents at the center of ZIP 81637: variable, well drained, pH about 7.3 (neutral).

Did spring come early in Gypsum, CO in 2026?

Spring leaf-out near 81637 came on Mar 31 in 2026, 25 days earlier than the 1991–2020 average (Apr 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Gypsum, CO?

Intermediate onions: the longest day near 81637 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 81637 change?

Yes. The 2012 USDA map put 81637 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.