Sunburst, 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.
Reliable performers under these conditions include cabbage, cranberry, turkish rocket, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Sunburst, 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 Sunburst 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 Sunburst — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Sunburst — the short answer
Sunburst, Montana: USDA zone 4a, about 152 days between hard freezes, across 1K acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~152
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Sunburst's average, not your lot's — a low corner or a tree line moves it. Against Sunburst's 152-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Sunburst
Each reading below is measured for Sunburst itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSunburst runs about 152 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
MeasuredSunburst 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 Sunburst is in
Sunburst sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Sunburst's own centroid rather than borrowed from Toole County.
What Grows in Sunburst
Every plant below cleared Sunburst's own zone 4a and its 152-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Sunburst?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 6; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 3 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Sunburst
Closest first, within ~10 miles of Sunburst. Listing isn't leaking, and distance isn't exposure.
- NWPMG00002 FORMER TEXACO SUNBURST WORKSBrownfields · 2200 ft
- NORTHERN TELEPHONE COOP INCUnderground Storage Tanks · 0.9 mi
- PAULS CONOCO BULKUnderground Storage Tanks · 0.9 mi
- SUTAS SUPPLY SOUTH SITEUnderground Storage Tanks · 0.9 mi
- SUTAS SUPPLY NORTH SITEUnderground Storage Tanks · 0.9 mi
- RICHARD DUNKUnderground Storage Tanks · 4.1 mi
- RIMROCK COLONY INCUnderground Storage Tanks · 4.1 mi
- SUNBURST SCHOOL DIST 2Underground Storage Tanks · 4.1 mi
- FRED & GEO CREEK STORAGEUnderground Storage Tanks · 4.1 mi
- BOW & ARROW RANCHUnderground Storage Tanks · 4.1 mi
- COMANCHE DRILLING COUnderground Storage Tanks · 4.6 mi
- 37N03W21DB 01Nitrate · 6.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Sunburst'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 Sunburst.
Total Sites
46
within ~10 miles of Sunburst
Risk Level
Low
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Sunburst
Severity Distribution
within ~10 miles of Sunburst
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Sunburst, Nitrate runs higher than the national average — 20 sites within ~10 miles of Sunburst. 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 Sunburst
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 Sunburst average
Your land is one point inside Sunburst
Everything above resolves to Sunburst as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Sunburst Average
Sunburst Average
- ●USDA Zones 4a, averaged across Sunburst
- ●One soil character for all of Sunburst
- ●Frost dates read at Sunburst's scale: May 4 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Sunburst's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Sunburst
Pull a site-specific report for your exact address in Sunburst, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Sunburst averages can't show:
We read public map data around Sunburst — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Sunburst average
How we know this about Sunburst
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 Sunburst’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 Sunburst
When does frost risk typically end in Sunburst?
The last hard freeze (28°F) in Sunburst typically lands around May 4, 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 25.
When is the first frost in Sunburst?
The first hard freeze (28°F) in Sunburst typically arrives around Oct 3, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 19, so the watching starts about Sep 3 — about 152 days after the spring freeze cleared.
How long is the growing season in Sunburst?
Measured between 28°F hard freezes, Sunburst sees about 152 frost-free days — roughly May 4 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 25 to Sep 19, about 117 days.
Is the soil safe to grow vegetables in Sunburst?
The federal record around Sunburst is light — 46 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (22), the nearest Brownfields record about 0.4 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 Sunburst?
From about Sep 3 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 3 (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 3. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Sunburst's scale — its 4a band and its 152-day season. Your yard writes its own version of Sunburst'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 Sunburst’s own scale
6 of the readings below were taken at Sunburst's own scale — its own ~152-day season between 28°F freezes, the 1,228 acres it covers and 46 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Sunburst's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Sunburst's own 28°F hard-freeze dates, about May 4 and Oct 3 and the ~152-day span between themNOAA 1991–2020 Climate Normals
- 46 documented contamination sites on the federal record near Sunburst, the closest Brownfields record about 0.4 miles out from the town centreFederal environmental registers
- Sunburst's boundary and the 1,228 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~152-day seasonGrowable Ground crop-matching engine
- The ecoregion at Sunburst's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Sunburst's 1,228 acres read through its county's SSURGO summaryfrom Toole County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Toole 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 Toole County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Sunburst's 1,228 acreswhy one lot differs from the next →
- Which side of Sunburst you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,228 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.4 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 Sunburst-wide figureread your own land →
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