Red Cliff, Colorado, sits in USDA hardiness zone 5a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, okra, cranberry, lavender, and pumpkin all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Red Cliff, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Red Cliff lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Red Cliff — soil, climate, flood, and parcel records. How we handle your address.
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Red Cliff — the short answer
Red Cliff, Colorado: USDA zone 5a, about 110 days between hard freezes, across 156 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jun 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~110
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 156 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5a is Red Cliff's average, not your lot's — a low corner or a tree line moves it. Against Red Cliff's 110-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Red Cliff
Each reading below is measured for Red Cliff itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredRed Cliff runs about 110 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredRed Cliff sits in USDA hardiness zone 5a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Red Cliff is in
Red Cliff sits in the Southern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Red Cliff's own centroid rather than borrowed from Eagle County.
What Grows in Red Cliff
Every plant below cleared Red Cliff's own zone 5a and its 110-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Red Cliff?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around May 5; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jun 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 20 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What's on the federal record near Red Cliff
Closest first, within ~10 miles of Red Cliff. Listing isn't leaking, and distance isn't exposure.
- Charles R WarrenUnderground Storage Tanks · 950 ft
- Conoco SsUnderground Storage Tanks · 2100 ft
- Golden WedgeMining · 2400 ft
- LibertyMining · 0.6 mi
- LIBERTY WELL AT WILLOW CREEKNitrate · 1.1 mi
- EAGLE RIVER ABANDONED MINESSuperfund · 1.2 mi
- Tip Top MineMining · 1.6 mi
- GilmanMining · 1.7 mi
- BELDEN CRIBBINGSSuperfund · 1.8 mi
- EagleMining · 1.8 mi
- Iron MaskMining · 1.8 mi
- Eagle MineMining · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Red Cliff's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Red Cliff.
Sources Checked
within ~10 miles of Red Cliff
Severity Distribution
within ~10 miles of Red Cliff
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Red Cliff, two things run higher than the national average within ~10 miles of Red Cliff — Mining (20 sites) and Superfund (3 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Red Cliff
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Red Cliff average
Your land is one point inside Red Cliff
Everything above resolves to Red Cliff as a whole — one PHZM band and one 28°F frost record, read across 156 acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Red Cliff Average
Red Cliff Average
- ●USDA Zones 5a, averaged across Red Cliff
- ●One soil character for all of Red Cliff
- ●Frost dates read at Red Cliff's scale: Jun 2 to Sep 20
YOUR Parcel
- ✓Your exact zone, not Red Cliff's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Red Cliff
Pull a site-specific report for your exact address in Red Cliff, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Red Cliff averages can't show:
We read public map data around Red Cliff — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Red Cliff average
How we know this about Red Cliff
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Red Cliff’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Red Cliff
When does frost risk typically end in Red Cliff?
The last hard freeze (28°F) in Red Cliff typically lands around Jun 2, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Jun 23.
When is the first frost in Red Cliff?
The first hard freeze (28°F) in Red Cliff typically arrives around Sep 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 6, so the watching starts about Aug 21 — about 110 days after the spring freeze cleared.
How long is the growing season in Red Cliff?
Measured between 28°F hard freezes, Red Cliff sees about 110 frost-free days — roughly Jun 2 through Sep 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 23 to Sep 6, about 75 days.
Is the soil safe to grow vegetables in Red Cliff?
The federal record around Red Cliff runs heavier than most — 143 documented sites, mostly Underground Storage Tanks entries (71), the nearest Underground Storage Tanks record about 0.2 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do gardeners stretch the season in Red Cliff?
With about 110 frost-free days between hard freezes, Red Cliff rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 138 to 166 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the Jun 2 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Red Cliff's scale — its 5a band and its 110-day season. Your yard writes its own version of Red Cliff's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Red Cliff’s own scale
6 of the readings below were taken at Red Cliff's own scale — its own ~110-day season between 28°F freezes, the 156 acres it covers and 143 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Red Cliff's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Red Cliff's own 28°F hard-freeze dates, about Jun 2 and Sep 20 and the ~110-day span between themNOAA 1991–2020 Climate Normals
- 143 documented contamination sites on the federal record near Red Cliff, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Red Cliff's boundary and the 156 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~110-day seasonGrowable Ground crop-matching engine
- The ecoregion at Red Cliff's own centroid, the Southern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Red Cliff's 156 acres read through its county's SSURGO summaryfrom Eagle County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Eagle County
- The growing challenges every Colorado grower plans around — written at state scale, so they stay on the state guidefrom Colorado
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Eagle County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Red Cliff's 156 acreswhy one lot differs from the next →
- Which side of Red Cliff you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 156 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Red Cliff-wide figureread your own land →
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