Shannon, Illinois, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
These conditions suit cabbage, cranberry, lavender, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Shannon, 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 Shannon 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 Shannon — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Shannon — the short answer
Shannon, Illinois: USDA zone 5a, about 186 days between hard freezes, across 308 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~186
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 308 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 Shannon's average, not your lot's — a low corner or a tree line moves it. Against Shannon's 186-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Shannon
Each reading below is measured for Shannon itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredShannon runs about 186 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
MeasuredShannon 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 Shannon is in
Shannon sits in the Central Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Shannon's own centroid rather than borrowed from Carroll County.
What Grows in Shannon
Every plant below cleared Shannon's own zone 5a and its 186-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Shannon?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 20 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Shannon
Closest first, within ~10 miles of Shannon. Listing isn't leaking, and distance isn't exposure.
- Truckenmiller DonaldUnderground Storage Tanks · 800 ft
- Appel SignsUnderground Storage Tanks · 1000 ft
- Carroll Service CoUnderground Storage Tanks · 1100 ft
- Lessman Grain CoUnderground Storage Tanks · 1200 ft
- Linker Oil CompanyUnderground Storage Tanks · 1300 ft
- STRATA GEOLOGICALBrownfields · 1400 ft
- Shannon High SchoolUnderground Storage Tanks · 1500 ft
- Shannon Grade SchoolUnderground Storage Tanks · 1500 ft
- Casey's General Store #1699Underground Storage Tanks · 1600 ft
- Get-N-GoUnderground Storage Tanks · 1600 ft
- Casey General StoresUnderground Storage Tanks · 1600 ft
- Milling MartinUnderground Storage Tanks · 2200 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Shannon'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 Shannon.
Total Sites
102
within ~10 miles of Shannon
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Shannon
Severity Distribution
within ~10 miles of Shannon
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Shannon, CAFO runs higher than the national average — 14 sites within ~10 miles of Shannon. That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Shannon
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 Shannon average
Your land is one point inside Shannon
Everything above resolves to Shannon as a whole — one PHZM band and one 28°F frost record, read across 308 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 Shannon Average
Shannon Average
- ●USDA Zones 5a, averaged across Shannon
- ●One soil character for all of Shannon
- ●Frost dates read at Shannon's scale: Apr 17 to Oct 20
YOUR Parcel
- ✓Your exact zone, not Shannon's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Shannon
Pull a site-specific report for your exact address in Shannon, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Shannon averages can't show:
We read public map data around Shannon — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Shannon average
How we know this about Shannon
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 Shannon’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 Shannon
When does frost risk typically end in Shannon?
The last hard freeze (28°F) in Shannon typically lands around Apr 17, 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 8.
When is the first frost in Shannon?
The first hard freeze (28°F) in Shannon typically arrives around Oct 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 6, so the watching starts about Sep 20 — about 186 days after the spring freeze cleared.
How long is the growing season in Shannon?
Measured between 28°F hard freezes, Shannon sees about 186 frost-free days — roughly Apr 17 through Oct 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 8 to Oct 6, about 151 days.
Is the soil safe to grow vegetables in Shannon?
The federal record around Shannon shows 102 documented sites, mostly Underground Storage Tanks entries (57), the nearest Underground Storage Tanks record about 0.1 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 Shannon?
From about Sep 20 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Shannon's scale — its 5a band and its 186-day season. Your yard writes its own version of Shannon'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 Shannon’s own scale
6 of the readings below were taken at Shannon's own scale — its own ~186-day season between 28°F freezes, the 308 acres it covers and 102 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Shannon's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Shannon's own 28°F hard-freeze dates, about Apr 17 and Oct 20 and the ~186-day span between themNOAA 1991–2020 Climate Normals
- 102 documented contamination sites on the federal record near Shannon, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Shannon's boundary and the 308 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~186-day seasonGrowable Ground crop-matching engine
- The ecoregion at Shannon's own centroid, the Central Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Shannon's 308 acres read through its county's SSURGO summaryfrom Carroll County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Carroll 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 Carroll County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Shannon's 308 acreswhy one lot differs from the next →
- Which side of Shannon you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 308 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Shannon-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisShannon sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides