Winthrop, Washington, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
On paper, cabbage, cranberry, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Winthrop, 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 Winthrop 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 Winthrop — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Winthrop — the short answer
Winthrop, Washington: USDA zone 5b, about 171 days between hard freezes, across 616 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~171
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 616 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 Winthrop's average, not your lot's — a low corner or a tree line moves it. Against Winthrop's 171-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Winthrop
Each reading below is measured for Winthrop itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWinthrop runs about 171 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
MeasuredWinthrop 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 Winthrop is in
Winthrop sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Winthrop's own centroid, and it is not what its county reads: Okanogan County is mostly North Cascades. The wider page above you is answering a different question about different ground.
What Grows in Winthrop
Every plant below cleared Winthrop's own zone 5b and its 171-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Winthrop?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Winthrop
Closest first, within ~10 miles of Winthrop. Listing isn't leaking, and distance isn't exposure.
- WINTHROP WORK CENTERUnderground Storage Tanks · 400 ft
- PASAYTEN CAFE TEXACOUnderground Storage Tanks · 750 ft
- PARDNERS, THE BEST LITTLE MINI MARKET IN WINTUnderground Storage Tanks · 1800 ft
- WINTHROP NFHUnderground Storage Tanks · 2400 ft
- WINTHROP MOTORSUnderground Storage Tanks · 2500 ft
- USDA FS OKANOGAN-WENATCHEE NF: LOWER WINTHROP COMPOUNDSuperfund · 0.7 mi
- METHOW FISH HATCHERYBrownfields · 1.3 mi
- PEARRYGIN LAKE STATE PARKUnderground Storage Tanks · 2.1 mi
- WDFW Methow Wildlife HdqtrsUnderground Storage Tanks · 3.1 mi
- FS-OKANOGAN-WENATCHEE NF, NORTH CASCADES SMOKE JUMPER BASESuperfund · 3.5 mi
- WA AGR OKANOGAN 5Brownfields · 3.5 mi
- Jones PropertyMining · 3.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Winthrop'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 Winthrop.
Total Sites
38
within ~10 miles of Winthrop
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Winthrop
Severity Distribution
within ~10 miles of Winthrop
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Winthrop, two things run higher than the national average within ~10 miles of Winthrop — Superfund (4 sites) and Mining (12 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Winthrop
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 Winthrop average
Your land is one point inside Winthrop
Everything above resolves to Winthrop as a whole — one PHZM band and one 28°F frost record, read across 616 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 Winthrop Average
Winthrop Average
- ●USDA Zones 5b, averaged across Winthrop
- ●One soil character for all of Winthrop
- ●Frost dates read at Winthrop's scale: Apr 22 to Oct 10
YOUR Parcel
- ✓Your exact zone, not Winthrop's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Winthrop
Pull a site-specific report for your exact address in Winthrop, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Winthrop averages can't show:
We read public map data around Winthrop — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Winthrop average
How we know this about Winthrop
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 Winthrop’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 Winthrop
When does frost risk typically end in Winthrop?
The last hard freeze (28°F) in Winthrop typically lands around Apr 22, 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 13.
When is the first frost in Winthrop?
The first hard freeze (28°F) in Winthrop typically arrives around Oct 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 26, so the watching starts about Sep 10 — about 171 days after the spring freeze cleared.
How long is the growing season in Winthrop?
Measured between 28°F hard freezes, Winthrop sees about 171 frost-free days — roughly Apr 22 through Oct 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 13 to Sep 26, about 136 days.
Is the soil safe to grow vegetables in Winthrop?
The federal record around Winthrop is a meaningful one — 38 documented sites, mostly Underground Storage Tanks entries (18), 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 Winthrop?
From about Sep 10 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 10 (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 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Winthrop's scale — its 5b band and its 171-day season. Your yard writes its own version of Winthrop'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 Winthrop’s own scale
6 of the readings below were taken at Winthrop's own scale — its own ~171-day season between 28°F freezes, the 616 acres it covers and 38 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Winthrop's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Winthrop's own 28°F hard-freeze dates, about Apr 22 and Oct 10 and the ~171-day span between themNOAA 1991–2020 Climate Normals
- 38 documented contamination sites on the federal record near Winthrop, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Winthrop's boundary and the 616 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~171-day seasonGrowable Ground crop-matching engine
- Winthrop sits in the Columbia Plateau — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Winthrop's 616 acres read through its county's SSURGO summaryfrom Okanogan County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Okanogan County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Okanogan County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Winthrop's 616 acreswhy one lot differs from the next →
- Which side of Winthrop you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 616 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 Winthrop-wide figureread your own land →