Winchester, Idaho, sits in USDA hardiness zone 6b — 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, blackberry, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Winchester, 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 Winchester 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 Winchester — soil, climate, flood, and parcel records. How we handle your address.
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Winchester — the short answer
Winchester, Idaho: USDA zone 6b, about 169 days between hard freezes, across 113 acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~169
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 113 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 Winchester's average, not your lot's — a low corner or a tree line moves it. Against Winchester's 169-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Winchester
Each reading below is measured for Winchester itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWinchester runs about 169 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
MeasuredWinchester 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 Winchester is in
Winchester sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Winchester's own centroid, and it is not what its county reads: Lewis County is mostly Columbia Plateau. The wider page above you is answering a different question about different ground.
What Grows in Winchester
Every plant below cleared Winchester's own zone 6b and its 169-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Winchester?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 16 — 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 Winchester
Closest first, within ~10 miles of Winchester. Listing isn't leaking, and distance isn't exposure.
- GARY FLORYUnderground Storage Tanks · 300 ft
- WINCHESTER STATE PARKUnderground Storage Tanks · 550 ft
- EVERGREEN HIGHWAY DISTRICTUnderground Storage Tanks · 650 ft
- 34N 02W 31DAA1Nitrate · 1400 ft
- CRAIG MOUNTAIN LUMBERSuperfund · 2500 ft
- 34N 02W 33BCC1Nitrate · 1.3 mi
- 34N 02W 22BCC1Nitrate · 3.3 mi
- 33N 02W 10AAB1Nitrate · 3.3 mi
- 34N 02W 10ACA1Nitrate · 5.6 mi
- 33N 03W 06DBD1Nitrate · 6.3 mi
- 32N 03W 01BBC1Nitrate · 6.6 mi
- WESTERN FARM SERVICE INCUnderground Storage Tanks · 6.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Winchester'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 Winchester.
Total Sites
45
within ~10 miles of Winchester
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Winchester
Severity Distribution
within ~10 miles of Winchester
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Winchester, Nitrate runs higher than the national average — 34 sites within ~10 miles of Winchester. That's not a problem with your land — it's information about it.
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 Winchester
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 Winchester average
Your land is one point inside Winchester
Everything above resolves to Winchester as a whole — one PHZM band and one 28°F frost record, read across 113 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 Winchester Average
Winchester Average
- ●USDA Zones 6b, averaged across Winchester
- ●One soil character for all of Winchester
- ●Frost dates read at Winchester's scale: Apr 30 to Oct 16
YOUR Parcel
- ✓Your exact zone, not Winchester's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Winchester
Pull a site-specific report for your exact address in Winchester, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Winchester averages can't show:
We read public map data around Winchester — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Winchester average
How we know this about Winchester
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 Winchester’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 Winchester
When does frost risk typically end in Winchester?
The last hard freeze (28°F) in Winchester typically lands around Apr 30, 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 21.
When is the first frost in Winchester?
The first hard freeze (28°F) in Winchester typically arrives around Oct 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 2, so the watching starts about Sep 16 — about 169 days after the spring freeze cleared.
How long is the growing season in Winchester?
Measured between 28°F hard freezes, Winchester sees about 169 frost-free days — roughly Apr 30 through Oct 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Oct 2, about 134 days.
Is the soil safe to grow vegetables in Winchester?
The federal record around Winchester is a meaningful one — 45 documented sites, mostly Nitrate entries (34), the nearest Underground Storage Tanks record under a tenth of a mile 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 Winchester?
From about Sep 16 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 16 (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 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Winchester's scale — its 6b band and its 169-day season. Your yard writes its own version of Winchester'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 Winchester’s own scale
6 of the readings below were taken at Winchester's own scale — its own ~169-day season between 28°F freezes, the 113 acres it covers and 45 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Winchester's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Winchester's own 28°F hard-freeze dates, about Apr 30 and Oct 16 and the ~169-day span between themNOAA 1991–2020 Climate Normals
- 45 documented contamination sites on the federal record near Winchester, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Winchester's boundary and the 113 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~169-day seasonGrowable Ground crop-matching engine
- Winchester sits in the Northern Rockies — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Winchester's 113 acres read through its county's SSURGO summaryfrom Lewis County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lewis County
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Lewis County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Winchester's 113 acreswhy one lot differs from the next →
- Which side of Winchester you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 113 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Winchester-wide figureread your own land →
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