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

Planting zone for 81633 — Dinosaur, CO

ZIP code 81633 (Dinosaur, Moffat County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 10 and the first fall frost October 4.

Where ZIP 81633 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 10
First frostOct 4
2012 zone5b

Same zone as on the 2012 map. 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 Dinosaur, 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 Dinosaur, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 10median — 50% chance of a later frost
Safe for tender plantsMay 27only 10% chance of frost after
First fall frostOctober 4median — 10% chance by Sep 20
Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 30 and returns around October 16.

From the NOAA station Massadona 3e, CO — 10 miles away, elevation 6,142 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 81633

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 29 – Apr 12
SpinachSow outdoors · Mar 29 – Apr 19
Broccoli, cabbageStart indoors · Mar 1 – Mar 15
Broccoli, cabbageTransplant · Apr 19 – May 3
Onion setsPlant outdoors · Apr 12 – Apr 26
PotatoesPlant outdoors · Apr 19 – May 3
LettuceSow outdoors · Apr 12 – Apr 26
Carrots, beetsSow outdoors · Apr 19 – May 3
TomatoesStart indoors · Mar 15 – Mar 29
TomatoesTransplant · May 17 – May 31
Peppers, eggplantStart indoors · Mar 1 – Mar 15
Peppers, eggplantTransplant · May 24 – Jun 7
BeansSow outdoors · May 17 – May 31
Sweet cornSow outdoors · May 17 – May 31
Cucumbers, squashSow outdoors · May 17 – May 31
Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23
GarlicPlant cloves · Sep 20 – Oct 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 10) and first fall frost (Oct 4) 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 81633 came on Mar 20 — 21 days earlier than the 1991–2020 average (Apr 10).

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 Dinosaur, CO.

Soil in Dinosaur, CO

The soil mapped at the center of ZIP 81633 is Grieves — loamy fine sand, somewhat excessively drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Grieves-Crestman complex, 10 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 81633; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dinosaur, CO

Summer high88 °Faverage high, July
Winter low12 °Faverage low, January
Hot days24days a year at 90 °F or more
Freezing nights179nights a year at 32 °F or less
Growing degree days2,484base 50 °F — the season’s usable heat
Longest day15 h 03 mindaylight on June 21
Shortest day9 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation14.4 inper year, rain and melted snow
Snowfall51 inper year

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 33 °F, low 12 °F 33°12° JanFebruary: average high 39 °F, low 15 °F 39°15° FebMarch: average high 51 °F, low 26 °F 51°26° MarApril: average high 59 °F, low 32 °F 59°32° AprMay: average high 69 °F, low 41 °F 69°41° MayJune: average high 82 °F, low 50 °F 82°50° JunJuly: average high 88 °F, low 57 °F 88°57° JulAugust: average high 86 °F, low 55 °F 86°55° AugSeptember: average high 77 °F, low 46 °F 77°46° SepOctober: average high 62 °F, low 35 °F 62°35° OctNovember: average high 47 °F, low 24 °F 47°24° NovDecember: average high 34 °F, low 12 °F 34°12° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 1.09 in precipitation, 13.3 in snowfall 1.1❄13 JanFebruary: 1.03 in precipitation, 8.1 in snowfall 1.0❄8 FebMarch: 1.25 in precipitation, 4.6 in snowfall 1.3❄5 MarApril: 1.32 in precipitation, 2.9 in snowfall 1.3❄3 AprMay: 1.59 in precipitation, 1 in snowfall 1.6❄1 MayJune: 0.85 in precipitation 0.8 JunJuly: 0.97 in precipitation 1.0 JulAugust: 0.96 in precipitation 1.0 AugSeptember: 1.56 in precipitation 1.6 SepOctober: 1.63 in precipitation, 4.3 in snowfall 1.6❄4 OctNovember: 1.04 in precipitation, 6.9 in snowfall 1.0❄7 NovDecember: 1.08 in precipitation, 10.1 in snowfall 1.1❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Massadona 3e, CO (10 mi away); precipitation: Massadona 3e, CO (10 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

816406a
Maybell, CO · 20 mi
816106a
Dinosaur, CO · 21 mi
816486a
Rangely, CO · 37 mi
816415b
Meeker, CO · 39 mi
816385b
Hamilton, CO · 44 mi
816255a
Craig, CO · 44 mi
840086a
Bonanza, UT · 45 mi
816506a
Rifle, CO · 48 mi

All 2 ZIP codes in Dinosaur → · Colorado planting zones →

Questions about 81633

What planting zone is ZIP code 81633?

ZIP code 81633 (Dinosaur, 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 Dinosaur, CO?

The median last spring frost (32 °F) near 81633 is May 10; after May 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Massadona 3e station.

When is the first frost in Dinosaur, CO?

The median first fall frost near 81633 is October 4, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 81633?

Start tomato seeds indoors around Mar 15 – Mar 29 and set transplants outside around May 17 – May 31, one to three weeks after the median last frost.

How much rain and snow does 81633 get?

About 14.4 inches of precipitation a year and 51 inches of snowfall (NOAA 1991–2020 normals, Massadona 3e station).

How hot do summers get in Dinosaur, CO?

The average high peaks at 88 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 81633 have?

The USDA soil survey maps Grieves at the center of ZIP 81633: loamy fine sand, somewhat excessively drained, pH about 7.9 (alkaline).

Did spring come early in Dinosaur, CO in 2026?

Spring leaf-out near 81633 came on Mar 20 in 2026, 21 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dinosaur, CO?

Long-day onions: the longest day near 81633 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).