Mount Clare, Illinois, sits in USDA hardiness zone 6b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, hazelnut, lavender, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Mount Clare, 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 Mount Clare 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 Mount Clare — soil, climate, flood, and parcel records. How we handle your address.
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Mount Clare — the short answer
Mount Clare, Illinois: USDA zone 6b, about 220 days between hard freezes, across 984 acres of town.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~220
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 984 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 6b is Mount Clare's average, not your lot's — a low corner or a tree line moves it. Against Mount Clare's 220-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mount Clare
Each reading below is measured for Mount Clare itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMount Clare runs about 220 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredMount Clare sits in USDA hardiness zone 6b.
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 Mount Clare is in
Mount Clare sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Mount Clare's own centroid rather than borrowed from Macoupin County.
What Grows in Mount Clare
Every plant below cleared Mount Clare's own zone 6b and its 220-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Mount Clare?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 4 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
What's on the federal record near Mount Clare
Closest first, within ~10 miles of Mount Clare. Listing isn't leaking, and distance isn't exposure.
- TJ's Enterprises of BenldUnderground Storage Tanks · 1.2 mi
- Fassero Oil CoUnderground Storage Tanks · 1.2 mi
- Rt&P AmocoUnderground Storage Tanks · 1.3 mi
- Quality MotorsUnderground Storage Tanks · 1.3 mi
- Benld City OfUnderground Storage Tanks · 1.4 mi
- Cordera TransferUnderground Storage Tanks · 1.5 mi
- Baima DistributingUnderground Storage Tanks · 1.5 mi
- Enrici LawrenceUnderground Storage Tanks · 1.5 mi
- QUALITY MOTORSBrownfields · 1.6 mi
- DOLLAR GENERAL STORE 2859Brownfields · 1.6 mi
- Brunetto Bros MobilUnderground Storage Tanks · 1.8 mi
- Caseys General Stores IncUnderground Storage Tanks · 1.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mount Clare'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 Mount Clare.
Total Sites
129
within ~10 miles of Mount Clare
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Mount Clare
Severity Distribution
within ~10 miles of Mount Clare
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mount Clare, two things run higher than the national average within ~10 miles of Mount Clare — CAFO (5 sites) and PFAS (4 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Mount Clare
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 Mount Clare average
Your land is one point inside Mount Clare
Everything above resolves to Mount Clare as a whole — one PHZM band and one 28°F frost record, read across 984 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 Mount Clare Average
Mount Clare Average
- ●USDA Zones 6b, averaged across Mount Clare
- ●One soil character for all of Mount Clare
- ●Frost dates read at Mount Clare's scale: Mar 29 to Nov 4
YOUR Parcel
- ✓Your exact zone, not Mount Clare's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mount Clare
Pull a site-specific report for your exact address in Mount Clare, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mount Clare averages can't show:
We read public map data around Mount Clare — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mount Clare average
How we know this about Mount Clare
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 Mount Clare’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 Mount Clare
When does frost risk typically end in Mount Clare?
The last hard freeze (28°F) in Mount Clare typically lands around Mar 29, 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 Apr 19.
When is the first frost in Mount Clare?
The first hard freeze (28°F) in Mount Clare typically arrives around Nov 4, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 21, so the watching starts about Oct 5 — about 220 days after the spring freeze cleared.
How long is the growing season in Mount Clare?
Measured between 28°F hard freezes, Mount Clare sees about 220 frost-free days — roughly Mar 29 through Nov 4, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 19 to Oct 21, about 185 days.
Is the soil safe to grow vegetables in Mount Clare?
The federal record around Mount Clare shows 129 documented sites, mostly Underground Storage Tanks entries (78), the nearest Underground Storage Tanks record about 1.2 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 Mount Clare?
From about Oct 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 Nov 4 (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 Nov 4. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mount Clare's scale — its 6b band and its 220-day season. Your yard writes its own version of Mount Clare'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 Mount Clare’s own scale
6 of the readings below were taken at Mount Clare's own scale — its own ~220-day season between 28°F freezes, the 984 acres it covers and 129 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mount Clare's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Mount Clare's own 28°F hard-freeze dates, about Mar 29 and Nov 4 and the ~220-day span between themNOAA 1991–2020 Climate Normals
- 129 documented contamination sites on the federal record near Mount Clare, the closest Underground Storage Tanks record about 1.2 miles out from the town centreFederal environmental registers
- Mount Clare's boundary and the 984 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~220-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mount Clare's own centroid, the Interior River Valleys and HillsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mount Clare's 984 acres read through its county's SSURGO summaryfrom Macoupin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Macoupin County
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Macoupin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mount Clare's 984 acreswhy one lot differs from the next →
- Which side of Mount Clare you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 984 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.2 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 Mount Clare-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisMount Clare sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides