King Arthur Park, Montana, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The conditions favor cabbage, cranberry, lavender, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in King Arthur Park, 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 King Arthur Park 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 King Arthur Park — soil, climate, flood, and parcel records. How we handle your address.
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King Arthur Park — the short answer
King Arthur Park, Montana: USDA zone 5a, about 153 days between hard freezes, across 296 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~153
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 296 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 King Arthur Park's average, not your lot's — a low corner or a tree line moves it. Against King Arthur Park's 153-day season, see what your own ground reads.
Your town runs its own season
King Arthur Park's own 30-year record measures about 153 days between 28°F killing freezes — 39 days longer than Gallatin County's ~114. Both are measured records, not estimates.
That gap is the whole reason a county average can mislead here. Plant against King Arthur Park's ~153-day season rather than the county figure — and the sun, slope and cold-air drainage on your specific lot move it again.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record. Both figures are measured records — this town’s own and its county’s. A town with no record of its own is absent here rather than estimated.
Soil varies lot by lot — soil types explained.
What this means for growing in King Arthur Park
Each reading below is measured for King Arthur Park itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredKing Arthur Park runs about 153 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
MeasuredKing Arthur Park 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 King Arthur Park is in
King Arthur Park sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at King Arthur Park's own centroid rather than borrowed from Gallatin County.
What Grows in King Arthur Park
Every plant below cleared King Arthur Park's own zone 5a and its 153-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in King Arthur Park?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 5 — 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 King Arthur Park
Closest first, within ~10 miles of King Arthur Park. Listing isn't leaking, and distance isn't exposure.
- RESSLER MOTOR COMPANYBrownfields · 1600 ft
- LIFE LINK INTERNATIONAL INCBrownfields · 1800 ft
- RV STORE INC./BIG SKY RV -RV DUMP STATIONBrownfields · 1800 ft
- EASTON CONCRETEBrownfields · 1800 ft
- SIMPSON HONDABrownfields · 1900 ft
- 02S05E17BBAA01Nitrate · 0.7 mi
- ABC RENTAL & EQUIPMENT SALESBrownfields · 0.9 mi
- VANDYKE IRRIGATION SERVICE INCUnderground Storage Tanks · 0.9 mi
- BRANDNER DESIGNBrownfields · 1.1 mi
- KNICK MACHININGBrownfields · 1.1 mi
- WOLFS BOZEMAN SUZUKIBrownfields · 1.1 mi
- BOB R NELSONUnderground Storage Tanks · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from King Arthur Park'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 King Arthur Park.
Total Sites
594
within ~10 miles of King Arthur Park
Risk Level
Elevated
Highest-severity
2 Superfund sites
Sources Checked
within ~10 miles of King Arthur Park
Severity Distribution
within ~10 miles of King Arthur Park
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around King Arthur Park, Nitrate runs higher than the national average — 248 sites within ~10 miles of King Arthur Park. 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 King Arthur Park
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 King Arthur Park average
Your land is one point inside King Arthur Park
Everything above resolves to King Arthur Park as a whole — and this is a town whose own 30-year record already runs a season its county’s does not. Your parcel sits at one point inside even that. 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 King Arthur Park Average
King Arthur Park Average
- ●USDA Zones 5a, averaged across King Arthur Park
- ●One soil character for all of King Arthur Park
- ●Frost dates read at King Arthur Park's scale: May 5 to Oct 5
YOUR Parcel
- ✓Your exact zone, not King Arthur Park's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in King Arthur Park
Pull a site-specific report for your exact address in King Arthur Park, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that King Arthur Park averages can't show:
We read public map data around King Arthur Park — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the King Arthur Park average
How we know this about King Arthur Park
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 King Arthur Park’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 King Arthur Park
When does frost risk typically end in King Arthur Park?
The last hard freeze (28°F) in King Arthur Park typically lands around May 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 May 26.
When is the first frost in King Arthur Park?
The first hard freeze (28°F) in King Arthur Park typically arrives around Oct 5, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 21, so the watching starts about Sep 5 — about 153 days after the spring freeze cleared.
How long is the growing season in King Arthur Park?
Measured between 28°F hard freezes, King Arthur Park sees about 153 frost-free days — roughly May 5 through Oct 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 26 to Sep 21, about 118 days.
Is the soil safe to grow vegetables in King Arthur Park?
The federal record around King Arthur Park is a meaningful one — 594 documented sites, mostly Nitrate entries (248), the nearest Brownfields record about 0.3 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in King Arthur Park?
From about Sep 5 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 5 (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 5. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at King Arthur Park's scale — its 5a band and its 153-day season. Your yard writes its own version of King Arthur Park'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 King Arthur Park’s own scale
6 of the readings below were taken at King Arthur Park's own scale — its own ~153-day season between 28°F freezes, the 296 acres it covers and 594 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- King Arthur Park's own USDA hardiness band, zones 5aUSDA PHZM 2023
- King Arthur Park's own 28°F hard-freeze dates, about May 5 and Oct 5 and the ~153-day span between themNOAA 1991–2020 Climate Normals
- 594 documented contamination sites on the federal record near King Arthur Park, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- King Arthur Park's boundary and the 296 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~153-day seasonGrowable Ground crop-matching engine
- The ecoregion at King Arthur Park's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so King Arthur Park's 296 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 King Arthur Park's 296 acreswhy one lot differs from the next →
- Which side of King Arthur Park you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 296 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.3 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 King Arthur Park-wide figureread your own land →
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