Port Byron, Illinois, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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 Port Byron, 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 Port Byron 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 Port Byron — soil, climate, flood, and parcel records. How we handle your address.
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Port Byron — the short answer
Port Byron, Illinois: USDA zone 5b, about 202 days between hard freezes, across 2K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~202
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town 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 5b is Port Byron's average, not your lot's — a low corner or a tree line moves it. Against Port Byron's 202-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Port Byron
Each reading below is measured for Port Byron itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPort Byron runs about 202 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
MeasuredPort Byron sits in USDA hardiness zone 5b.
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 Port Byron is in
Port Byron sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Port Byron's own centroid rather than borrowed from Rock Island County.
What Grows in Port Byron
Every plant below cleared Port Byron's own zone 5b and its 202-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Port Byron?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 10; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
What's on the federal record near Port Byron
Closest first, within ~10 miles of Port Byron. Listing isn't leaking, and distance isn't exposure.
- DOLLAR GENERAL STORE 6165Brownfields · 2200 ft
- Chuck Hartz Service StationUnderground Storage Tanks · 0.8 mi
- Commercial Towel SerUnderground Storage Tanks · 0.9 mi
- Casey's General StoreUnderground Storage Tanks · 1.1 mi
- Handy StopUnderground Storage Tanks · 1.1 mi
- CODY MARTUnderground Storage Tanks · 1.2 mi
- D-XUnderground Storage Tanks · 1.2 mi
- SANDSTROM PRODUCTS COBrownfields · 1.4 mi
- SANDSTROM PRODUCTS COToxics Release Inventory · 1.4 mi
- Not KnownUnderground Storage Tanks · 1.5 mi
- GILLESPIE AUTOBrownfields · 1.8 mi
- CITY WELL #1Underground Storage Tanks · 1.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Port Byron'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 Port Byron.
Total Sites
263
within ~10 miles of Port Byron
Risk Level
Elevated
Highest-severity
5 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Port Byron
Severity Distribution
within ~10 miles of Port Byron
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Port Byron, two things run higher than the national average within ~10 miles of Port Byron — CAFO (6 sites) and Superfund (5 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Port Byron
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 Port Byron average
Your land is one point inside Port Byron
Everything above resolves to Port Byron 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 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 Port Byron Average
Port Byron Average
- ●USDA Zones 5b, averaged across Port Byron
- ●One soil character for all of Port Byron
- ●Frost dates read at Port Byron's scale: Apr 7 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Port Byron's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Port Byron
Pull a site-specific report for your exact address in Port Byron, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Port Byron averages can't show:
We read public map data around Port Byron — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Port Byron average
How we know this about Port Byron
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 Port Byron’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 Port Byron
When does frost risk typically end in Port Byron?
The last hard freeze (28°F) in Port Byron typically lands around Apr 7, 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 28.
When is the first frost in Port Byron?
The first hard freeze (28°F) in Port Byron typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 202 days after the spring freeze cleared.
How long is the growing season in Port Byron?
Measured between 28°F hard freezes, Port Byron sees about 202 frost-free days — roughly Apr 7 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 28 to Oct 12, about 167 days.
Is the soil safe to grow vegetables in Port Byron?
The federal record around Port Byron is a meaningful one — 263 documented sites, mostly Underground Storage Tanks entries (143), the nearest Brownfields record about 0.4 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 Port Byron?
From about Sep 26 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Port Byron's scale — its 5b band and its 202-day season. Your yard writes its own version of Port Byron'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 Port Byron’s own scale
6 of the readings below were taken at Port Byron's own scale — its own ~202-day season between 28°F freezes, the 1,554 acres it covers and 263 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Port Byron's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Port Byron's own 28°F hard-freeze dates, about Apr 7 and Oct 26 and the ~202-day span between themNOAA 1991–2020 Climate Normals
- 263 documented contamination sites on the federal record near Port Byron, the closest Brownfields record about 0.4 miles out from the town centreFederal environmental registers
- Port Byron's boundary and the 1,554 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~202-day seasonGrowable Ground crop-matching engine
- The ecoregion at Port Byron'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 Port Byron's 1,554 acres read through its county's SSURGO summaryfrom Rock Island County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Rock Island 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 Rock Island County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Port Byron's 1,554 acreswhy one lot differs from the next →
- Which side of Port Byron you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,554 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 Port Byron-wide figureread your own land →
More in Illinois
Wider growing context
What grows across IllinoisPort Byron sits outside our named growing regions, so Illinois as a whole is its closest context here.
Nearby growing guides