Big Sky, Montana, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, zucchini, cranberry, cilantro, and okra all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Big Sky, 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 Big Sky 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 Big Sky — soil, climate, flood, and parcel records. How we handle your address.
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Big Sky — the short answer
Big Sky, Montana: USDA zone 4b, about 101 days between hard freezes, across 77K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jun 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~101
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 77K 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 4b is Big Sky's average, not your lot's — a low corner or a tree line moves it. Against Big Sky's 101-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Big Sky
Each reading below is measured for Big Sky itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBig Sky runs about 101 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
MeasuredBig Sky sits in USDA hardiness zone 4b.
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 Big Sky is in
Big Sky sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Big Sky's own centroid rather than borrowed from Gallatin County.
What Grows in Big Sky
Every plant below cleared Big Sky's own zone 4b and its 101-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Big Sky?
Almost never — the real question is what to plant next. Cool-season crops can go in from around May 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jun 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 14 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Big Sky
Closest first, within ~10 miles of Big Sky. Listing isn't leaking, and distance isn't exposure.
- TOWN CENTER HOTELBrownfields · 1.4 mi
- BOZEMAN HEALTH BIG SKY MEDICAL CENTERBrownfields · 1.5 mi
- TOM GERRARDUnderground Storage Tanks · 2.0 mi
- Last Chance ProspectMining · 3.2 mi
- YELLOWSTONE CLUBBrownfields · 3.4 mi
- BIG SKY COUNTY WATER AND SEWER DIST 363PFAS · 3.5 mi
- WATERMARK HOMEUnderground Storage Tanks · 3.7 mi
- CASEYS #6Underground Storage Tanks · 3.8 mi
- BIG SKY CONOCOUnderground Storage Tanks · 3.8 mi
- BIG SKY OF MONTANA SHOPUnderground Storage Tanks · 3.9 mi
- BIG SKY GOLF COURSEBrownfields · 3.9 mi
- Unidentified Copper OccurrenceMining · 5.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Big Sky'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 Big Sky.
Total Sites
21
within ~10 miles of Big Sky
Risk Level
Moderate
Highest-severity
9 mining sites (prospects, none worked)
Sources Checked
within ~10 miles of Big Sky
Severity Distribution
within ~10 miles of Big Sky
Highest-Severity Sites
Know Before You Grow
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Big Sky
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 Big Sky average
Your land is one point inside Big Sky
Everything above resolves to Big Sky as a whole — one PHZM band and one 28°F frost record, read across 77K 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 Big Sky Average
Big Sky Average
- ●USDA Zones 4b, averaged across Big Sky
- ●One soil character for all of Big Sky
- ●Frost dates read at Big Sky's scale: Jun 5 to Sep 14
YOUR Parcel
- ✓Your exact zone, not Big Sky's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Big Sky
Pull a site-specific report for your exact address in Big Sky, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Big Sky averages can't show:
We read public map data around Big Sky — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Big Sky average
How we know this about Big Sky
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 Big Sky’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 Big Sky
When does frost risk typically end in Big Sky?
The last hard freeze (28°F) in Big Sky typically lands around Jun 5, 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 26.
When is the first frost in Big Sky?
The first hard freeze (28°F) in Big Sky typically arrives around Sep 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Aug 31, so the watching starts about Aug 15 — about 101 days after the spring freeze cleared.
How long is the growing season in Big Sky?
Measured between 28°F hard freezes, Big Sky sees about 101 frost-free days — roughly Jun 5 through Sep 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 26 to Aug 31, about 66 days.
Is the soil safe to grow vegetables in Big Sky?
The federal record around Big Sky shows 21 documented sites, mostly Mining entries (9), the nearest Brownfields record about 1.4 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do gardeners stretch the season in Big Sky?
With about 101 frost-free days between hard freezes, Big Sky 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 129 to 157 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the Jun 5 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Big Sky's scale — its 4b band and its 101-day season. Your yard writes its own version of Big Sky'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 Big Sky’s own scale
6 of the readings below were taken at Big Sky's own scale — its own ~101-day season between 28°F freezes, the 76,803 acres it covers and 21 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Big Sky's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Big Sky's own 28°F hard-freeze dates, about Jun 5 and Sep 14 and the ~101-day span between themNOAA 1991–2020 Climate Normals
- 21 documented contamination sites on the federal record near Big Sky, the closest Brownfields record about 1.4 miles out from the town centreFederal environmental registers
- Big Sky's boundary and the 76,803 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~101-day seasonGrowable Ground crop-matching engine
- The ecoregion at Big Sky's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Big Sky's 76,803 acres read through its county's SSURGO summaryfrom Gallatin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Gallatin 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 Gallatin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Big Sky's 76,803 acreswhy one lot differs from the next →
- Which side of Big Sky you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 76,803 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 1.4 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 Big Sky-wide figureread your own land →
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