Havre, Montana, sits in USDA hardiness zone 4a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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 Havre, 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 Havre 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 Havre — soil, climate, flood, and parcel records. How we handle your address.
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Havre — the short answer
Havre, Montana: USDA zone 4a, about 154 days between hard freezes, across 2K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~154
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 Havre's average, not your lot's — a low corner or a tree line moves it. Against Havre's 154-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Havre
Each reading below is measured for Havre itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHavre runs about 154 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
MeasuredHavre 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 Havre is in
Havre sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Havre's own centroid rather than borrowed from Hill County.
What Grows in Havre
Every plant below cleared Havre's own zone 4a and its 154-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Havre?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 2 — 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 Havre
Closest first, within ~10 miles of Havre. Listing isn't leaking, and distance isn't exposure.
- J & P REAL ESTATEUnderground Storage Tanks · 1700 ft
- BN CHILDS MICROWAVE BELKNAPUnderground Storage Tanks · 1700 ft
- KOA OF HAVREUnderground Storage Tanks · 1700 ft
- BALTRUSCH CONSTRUCTION CO INC N SITEUnderground Storage Tanks · 1700 ft
- MIDAS MUFFLER HAVREUnderground Storage Tanks · 1700 ft
- HAVRE AIR FORCE STATION BLDG 44Underground Storage Tanks · 1700 ft
- HAVRE AIR FORCE STATION BLDG 42Underground Storage Tanks · 1700 ft
- EAST END COLONYUnderground Storage Tanks · 1700 ft
- BN CEMENT HILL MICROWAVEUnderground Storage Tanks · 1700 ft
- LEROY KELLERUnderground Storage Tanks · 1700 ft
- H STERRETTUnderground Storage Tanks · 1700 ft
- NORDLING & TWEETEN ENTUnderground Storage Tanks · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Havre'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 Havre.
Total Sites
141
within ~10 miles of Havre
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Havre
Severity Distribution
within ~10 miles of Havre
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Havre, Underground Storage Tanks runs higher than the national average — 102 sites within ~10 miles of Havre. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Havre
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 Havre average
Your land is one point inside Havre
Everything above resolves to Havre as a whole — one PHZM band and one 28°F frost record, read across 2K 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 city 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 Havre Average
Havre Average
- ●USDA Zones 4a, averaged across Havre
- ●One soil character for all of Havre
- ●Frost dates read at Havre's scale: May 1 to Oct 2
YOUR Parcel
- ✓Your exact zone, not Havre's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Havre
Pull a site-specific report for your exact address in Havre, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Havre averages can't show:
We read public map data around Havre — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Havre average
How we know this about Havre
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Havre’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 city grain anywhere on this page — there is no city-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 Havre
When does frost risk typically end in Havre?
The last hard freeze (28°F) in Havre typically lands around May 1, 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 22.
When is the first frost in Havre?
The first hard freeze (28°F) in Havre typically arrives around Oct 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 18, so the watching starts about Sep 2 — about 154 days after the spring freeze cleared.
How long is the growing season in Havre?
Measured between 28°F hard freezes, Havre sees about 154 frost-free days — roughly May 1 through Oct 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 22 to Sep 18, about 119 days.
Is the soil safe to grow vegetables in Havre?
The federal record around Havre shows 141 documented sites, mostly Underground Storage Tanks entries (102), the nearest Underground Storage Tanks record about 0.3 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 I protect my plants from frost in Havre?
From about Sep 2 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 2 (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 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Havre's scale — its 4a band and its 154-day season. Your yard writes its own version of Havre'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 Havre’s own scale
6 of the readings below were taken at Havre's own scale — its own ~154-day season between 28°F freezes, the 2,374 acres it covers and 141 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Havre's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Havre's own 28°F hard-freeze dates, about May 1 and Oct 2 and the ~154-day span between themNOAA 1991–2020 Climate Normals
- 141 documented contamination sites on the federal record near Havre, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Havre's boundary and the 2,374 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~154-day seasonGrowable Ground crop-matching engine
- The ecoregion at Havre's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Havre's 2,374 acres read through its county's SSURGO summaryfrom Hill County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hill 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 Hill County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Havre's 2,374 acreswhy one lot differs from the next →
- Which side of Havre you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,374 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Havre-wide figureread your own land →
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