Twin Hills Colony, Montana, sits in USDA hardiness zone 4a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect cabbage, cranberry, turkish rocket, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Twin Hills Colony, 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 Twin Hills Colony 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 Twin Hills Colony — soil, climate, flood, and parcel records. How we handle your address.
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Twin Hills Colony — the short answer
Twin Hills Colony, Montana: USDA zone 4a, about 157 days between hard freezes, across 234 acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~157
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 234 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 4a is Twin Hills Colony's average, not your lot's — a low corner or a tree line moves it. Against Twin Hills Colony's 157-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Twin Hills Colony
Each reading below is measured for Twin Hills Colony itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTwin Hills Colony runs about 157 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredTwin Hills Colony sits in USDA hardiness zone 4a.
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 Twin Hills Colony is in
Twin Hills Colony sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Twin Hills Colony's own centroid rather than borrowed from Chouteau County.
What Grows in Twin Hills Colony
Every plant below cleared Twin Hills Colony's own zone 4a and its 157-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Twin Hills Colony?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 6 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Twin Hills Colony
Closest first, within ~10 miles of Twin Hills Colony. Listing isn't leaking, and distance isn't exposure.
- TWIN HILLS COLONYCAFO · 200 ft
- 26N04E03DBAC01Nitrate · 6.3 mi
- 27N07E31CBAD01Nitrate · 8.8 mi
- 27N07E31CABC01Nitrate · 8.9 mi
Measured from Twin Hills Colony'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 Twin Hills Colony.
Total Sites
7
within ~10 miles of Twin Hills Colony
Risk Level
Low
Highest-severity
1 concentrated animal feeding operation
Severity Distribution
within ~10 miles of Twin Hills Colony
Highest-Severity Sites
Know Before You Grow
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Large animal operations push nitrates and bacteria downstream. Below one, test your water.
Check your specific parcel in Twin Hills Colony
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 Twin Hills Colony average
Your land is one point inside Twin Hills Colony
Everything above resolves to Twin Hills Colony as a whole — one PHZM band and one 28°F frost record, read across 234 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 Twin Hills Colony Average
Twin Hills Colony Average
- ●USDA Zones 4a, averaged across Twin Hills Colony
- ●One soil character for all of Twin Hills Colony
- ●Frost dates read at Twin Hills Colony's scale: May 2 to Oct 6
YOUR Parcel
- ✓Your exact zone, not Twin Hills Colony's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Twin Hills Colony
Pull a site-specific report for your exact address in Twin Hills Colony, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Twin Hills Colony averages can't show:
We read public map data around Twin Hills Colony — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Twin Hills Colony average
How we know this about Twin Hills Colony
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 Twin Hills Colony’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 Twin Hills Colony
When does frost risk typically end in Twin Hills Colony?
The last hard freeze (28°F) in Twin Hills Colony typically lands around May 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 May 23.
When is the first frost in Twin Hills Colony?
The first hard freeze (28°F) in Twin Hills Colony typically arrives around Oct 6, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 22, so the watching starts about Sep 6 — about 157 days after the spring freeze cleared.
How long is the growing season in Twin Hills Colony?
Measured between 28°F hard freezes, Twin Hills Colony sees about 157 frost-free days — roughly May 2 through Oct 6, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Sep 22, about 122 days.
Is the soil safe to grow vegetables in Twin Hills Colony?
The federal record around Twin Hills Colony is light — 7 documented sites across the 9 federal source types we checked, mostly Nitrate entries (6), the nearest CAFO record under a tenth of a mile out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Twin Hills Colony?
From about Sep 6 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 6 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 6. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Twin Hills Colony's scale — its 4a band and its 157-day season. Your yard writes its own version of Twin Hills Colony'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 Twin Hills Colony’s own scale
6 of the readings below were taken at Twin Hills Colony's own scale — its own ~157-day season between 28°F freezes, the 234 acres it covers and 7 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Twin Hills Colony's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Twin Hills Colony's own 28°F hard-freeze dates, about May 2 and Oct 6 and the ~157-day span between themNOAA 1991–2020 Climate Normals
- 7 documented contamination sites on the federal record near Twin Hills Colony, the closest CAFO record under a tenth of a mile out from the town centreFederal environmental registers
- Twin Hills Colony's boundary and the 234 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~157-day seasonGrowable Ground crop-matching engine
- The ecoregion at Twin Hills Colony's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Twin Hills Colony's 234 acres read through its county's SSURGO summaryfrom Chouteau County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Chouteau County
- The growing challenges every Montana grower plans around — written at state scale, so they stay on the state guidefrom Montana
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Chouteau County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Twin Hills Colony's 234 acreswhy one lot differs from the next →
- Which side of Twin Hills Colony you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 234 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest CAFO record under a tenth of a mile 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 Twin Hills Colony-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaTwin Hills Colony sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides