Square Butte, 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.
Growers here do well with cabbage, cranberry, turkish rocket, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Square Butte, 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 Square Butte 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 Square Butte — soil, climate, flood, and parcel records. How we handle your address.
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Square Butte — the short answer
Square Butte, Montana: USDA zone 4a, about 161 days between hard freezes, across 176 acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~161
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 176 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 Square Butte's average, not your lot's — a low corner or a tree line moves it. Against Square Butte's 161-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Square Butte
Each reading below is measured for Square Butte itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSquare Butte runs about 161 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
MeasuredSquare Butte 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 Square Butte is in
Square Butte sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Square Butte's own centroid rather than borrowed from Chouteau County.
What Grows in Square Butte
Every plant below cleared Square Butte's own zone 4a and its 161-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Square Butte?
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 Apr 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 8 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Square Butte
Closest first, within ~10 miles of Square Butte. Listing isn't leaking, and distance isn't exposure.
- CENTRAL MONTANA RAILUnderground Storage Tanks · 1100 ft
- DALE & RANDY ROUDEBUSHUnderground Storage Tanks · 1100 ft
- BIG SAG RANCHUnderground Storage Tanks · 1100 ft
- GERALDINE AIRPORT 805695Underground Storage Tanks · 1100 ft
- PHIL TADEJ RANCH COUnderground Storage Tanks · 1100 ft
- EAGLE BUTTE FARM INCUnderground Storage Tanks · 1100 ft
- GERALDINE AIRPORT 808215Underground Storage Tanks · 1100 ft
- 20N12E10CCCA01Nitrate · 1.2 mi
- JOYCE FUEL & FEEDS GERALDINEUnderground Storage Tanks · 2.4 mi
- 20N12E13BCDB01Nitrate · 2.5 mi
- 20N13E05ABCB01Nitrate · 4.3 mi
- 21N13E07BBBC01Nitrate · 6.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Square Butte'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 Square Butte.
Sources Checked
within ~10 miles of Square Butte
Severity Distribution
within ~10 miles of Square Butte
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Square Butte, Nitrate runs higher than the national average — 18 sites within ~10 miles of Square Butte. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Square Butte
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 Square Butte average
Your land is one point inside Square Butte
Everything above resolves to Square Butte as a whole — one PHZM band and one 28°F frost record, read across 176 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 Square Butte Average
Square Butte Average
- ●USDA Zones 4a, averaged across Square Butte
- ●One soil character for all of Square Butte
- ●Frost dates read at Square Butte's scale: Apr 30 to Oct 8
YOUR Parcel
- ✓Your exact zone, not Square Butte's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Square Butte
Pull a site-specific report for your exact address in Square Butte, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Square Butte averages can't show:
We read public map data around Square Butte — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Square Butte average
How we know this about Square Butte
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 Square Butte’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 Square Butte
When does frost risk typically end in Square Butte?
The last hard freeze (28°F) in Square Butte typically lands around Apr 30, 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 21.
When is the first frost in Square Butte?
The first hard freeze (28°F) in Square Butte typically arrives around Oct 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 24, so the watching starts about Sep 8 — about 161 days after the spring freeze cleared.
How long is the growing season in Square Butte?
Measured between 28°F hard freezes, Square Butte sees about 161 frost-free days — roughly Apr 30 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Sep 24, about 126 days.
Is the soil safe to grow vegetables in Square Butte?
The federal record around Square Butte is light — 33 documented sites across the 9 federal source types we checked, mostly Nitrate entries (18), the nearest Underground Storage Tanks record about 0.2 miles 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 Square Butte?
From about Sep 8 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Square Butte's scale — its 4a band and its 161-day season. Your yard writes its own version of Square Butte'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 Square Butte’s own scale
6 of the readings below were taken at Square Butte's own scale — its own ~161-day season between 28°F freezes, the 176 acres it covers and 33 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Square Butte's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Square Butte's own 28°F hard-freeze dates, about Apr 30 and Oct 8 and the ~161-day span between themNOAA 1991–2020 Climate Normals
- 33 documented contamination sites on the federal record near Square Butte, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Square Butte's boundary and the 176 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~161-day seasonGrowable Ground crop-matching engine
- The ecoregion at Square Butte's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Square Butte's 176 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 Square Butte's 176 acreswhy one lot differs from the next →
- Which side of Square Butte you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 176 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 Square Butte-wide figureread your own land →
More in Montana
Wider growing context
What grows across MontanaSquare Butte sits outside our named growing regions, so Montana as a whole is its closest context here.
Nearby growing guides