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

Planting zone for 80733 — Hillrose, CO

ZIP code 80733 (Hillrose, Morgan County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 6 and the first fall frost October 8.

Where ZIP 80733 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 6
First frostOct 8
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 Hillrose, 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 Hillrose, CO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 6median — 50% chance of a later frost
Safe for tender plantsMay 19only 10% chance of frost after
First fall frostOctober 8median — 10% chance by Sep 27
Growing season155 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 17.

From the NOAA station Akron Washington Co. Airport, CO — 19 miles away, elevation 4,662 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 80733

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 25 – Apr 8
SpinachSow outdoors · Mar 25 – Apr 15
Broccoli, cabbageStart indoors · Feb 25 – Mar 11
Broccoli, cabbageTransplant · Apr 15 – Apr 29
Onion setsPlant outdoors · Apr 8 – Apr 22
PotatoesPlant outdoors · Apr 15 – Apr 29
LettuceSow outdoors · Apr 8 – Apr 22
Carrots, beetsSow outdoors · Apr 15 – Apr 29
TomatoesStart indoors · Mar 11 – Mar 25
TomatoesTransplant · May 13 – May 27
Peppers, eggplantStart indoors · Feb 25 – Mar 11
Peppers, eggplantTransplant · May 20 – Jun 3
BeansSow outdoors · May 13 – May 27
Sweet cornSow outdoors · May 13 – May 27
Cucumbers, squashSow outdoors · May 13 – May 27
Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27
GarlicPlant cloves · Sep 24 – Oct 29
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 8) 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 80733 came on Mar 1 — 24 days earlier than the 1991–2020 average (Mar 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 Hillrose, CO.

Soil in Hillrose, CO

The soil mapped at the center of ZIP 80733 is Nunn — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Nunn clay loam, 0 to 1 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 80733; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hillrose, CO

Summer high89 °Faverage high, July
Winter low17 °Faverage low, January
Hot days42days a year at 90 °F or more
Freezing nights157nights a year at 32 °F or less
Growing degree days2,954base 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)
Precipitation15.7 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 41 °F, low 17 °F 41°17° JanFebruary: average high 44 °F, low 19 °F 44°19° FebMarch: average high 54 °F, low 27 °F 54°27° MarApril: average high 61 °F, low 34 °F 61°34° AprMay: average high 71 °F, low 43 °F 71°43° MayJune: average high 83 °F, low 54 °F 83°54° JunJuly: average high 89 °F, low 60 °F 89°60° JulAugust: average high 87 °F, low 59 °F 87°59° AugSeptember: average high 78 °F, low 50 °F 78°50° SepOctober: average high 64 °F, low 37 °F 64°37° OctNovember: average high 51 °F, low 26 °F 51°26° NovDecember: average high 41 °F, low 18 °F 41°18° Dec

Precipitation by month inches

0″1″2″3″January: 0.26 in precipitation 0.3 JanFebruary: 0.40 in precipitation 0.4 FebMarch: 0.81 in precipitation 0.8 MarApril: 1.37 in precipitation 1.4 AprMay: 2.77 in precipitation 2.8 MayJune: 2.82 in precipitation 2.8 JunJuly: 2.20 in precipitation 2.2 JulAugust: 1.91 in precipitation 1.9 AugSeptember: 1.30 in precipitation 1.3 SepOctober: 1.08 in precipitation 1.1 OctNovember: 0.41 in precipitation 0.4 NovDecember: 0.34 in precipitation 0.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Akron Washington Co. Airport, CO (19 mi away); precipitation: Hillrose 2.5 Ssw, CO (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

807505b
Snyder, CO · 8 mi
807235b
Brush, CO · 12 mi
807415b
Merino, CO · 14 mi
807225b
Atwood, CO · 17 mi
807545b
Stoneham, CO · 23 mi
807515b
Sterling, CO · 24 mi
807015b
Fort Morgan, CO · 24 mi
807205b
Akron, CO · 25 mi

Colorado planting zones →

Questions about 80733

What planting zone is ZIP code 80733?

ZIP code 80733 (Hillrose, 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 Hillrose, CO?

The median last spring frost (32 °F) near 80733 is May 6; after May 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Akron Washington Co. Airport station.

When is the first frost in Hillrose, CO?

The median first fall frost near 80733 is October 8, giving a median frost-free growing season of 155 days.

When should I plant tomatoes in 80733?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 80733 get?

About 15.7 inches of precipitation a year (NOAA 1991–2020 normals, Hillrose 2.5 Ssw station).

How hot do summers get in Hillrose, CO?

The average high peaks at 89 °F in July, with about 42 days a year at 90 °F or more.

What kind of soil does 80733 have?

The USDA soil survey maps Nunn at the center of ZIP 80733: clay loam, well drained, pH about 7.2 (neutral).

Did spring come early in Hillrose, CO in 2026?

Spring leaf-out near 80733 came on Mar 1 in 2026, 24 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hillrose, CO?

Long-day onions: the longest day near 80733 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 80733 change?

Yes. The 2012 USDA map put 80733 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.