Port Washington, Wisconsin, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Among the crops suited to this profile: cabbage, hazelnut, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Port Washington, 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 Washington 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 Washington — soil, climate, flood, and parcel records. How we handle your address.
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Port Washington — the short answer
Port Washington, Wisconsin: USDA zone 6a, about 209 days between hard freezes, across 4K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 5
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~209
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K 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 6a is Port Washington's average, not your lot's — a low corner or a tree line moves it. Against Port Washington's 209-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Port Washington
Each reading below is measured for Port Washington itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPort Washington runs about 209 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 Washington sits in USDA hardiness zone 6a.
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 Washington is in
Port Washington sits in the Southeastern Wisconsin Till Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Port Washington's own centroid rather than borrowed from Ozaukee County.
What Grows in Port Washington
Every plant below cleared Port Washington's own zone 6a and its 209-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Port Washington?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 5 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Port Washington
Closest first, within ~10 miles of Port Washington. Listing isn't leaking, and distance isn't exposure.
- ISABEL FLIERLUnderground Storage Tanks · 400 ft
- MODERN EQUIPMENT COUnderground Storage Tanks · 500 ft
- MODERN EQUIPMENT COBrownfields · 550 ft
- MODERN EQUIPMENT COToxics Release Inventory · 550 ft
- MILLIPORESIGMA - PORT WASHINGTONBrownfields · 550 ft
- PARADEIS OIL COUnderground Storage Tanks · 550 ft
- Sika CorpUnderground Storage Tanks · 550 ft
- VEOLIA ES TECHNICAL SOLUTIONS LLCBrownfields · 700 ft
- VEOLIA ES TECHNICAL SOLUTIONS LLCToxics Release Inventory · 700 ft
- HILLSIDE AUTO PARTSUnderground Storage Tanks · 850 ft
- SCHMIT BROS DODGEUnderground Storage Tanks · 950 ft
- SCHMIT BROS DODGEBrownfields · 950 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Port Washington'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 Washington.
Total Sites
622
within ~10 miles of Port Washington
Risk Level
Elevated
Highest-severity
7 Superfund sites
Sources Checked
within ~10 miles of Port Washington
Severity Distribution
within ~10 miles of Port Washington
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Port Washington, Toxics Release Inventory runs higher than the national average — 45 sites within ~10 miles of Port Washington. That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Port Washington
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 Washington average
Your land is one point inside Port Washington
Everything above resolves to Port Washington as a whole — one PHZM band and one 28°F frost record, read across 4K 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 Port Washington Average
Port Washington Average
- ●USDA Zones 6a, averaged across Port Washington
- ●One soil character for all of Port Washington
- ●Frost dates read at Port Washington's scale: Apr 10 to Nov 5
YOUR Parcel
- ✓Your exact zone, not Port Washington's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Port Washington
Pull a site-specific report for your exact address in Port Washington, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Port Washington averages can't show:
We read public map data around Port Washington — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Port Washington average
How we know this about Port Washington
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 Port Washington’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 Port Washington
When does frost risk typically end in Port Washington?
The last hard freeze (28°F) in Port Washington typically lands around Apr 10, 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 1.
When is the first frost in Port Washington?
The first hard freeze (28°F) in Port Washington typically arrives around Nov 5, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 22, so the watching starts about Oct 6 — about 209 days after the spring freeze cleared.
How long is the growing season in Port Washington?
Measured between 28°F hard freezes, Port Washington sees about 209 frost-free days — roughly Apr 10 through Nov 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 22, about 174 days.
Is the soil safe to grow vegetables in Port Washington?
The federal record around Port Washington is a meaningful one — 622 documented sites, mostly Underground Storage Tanks entries (304), 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 Port Washington?
From about Oct 6 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 5 (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 5. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Port Washington's scale — its 6a band and its 209-day season. Your yard writes its own version of Port Washington'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 Washington’s own scale
6 of the readings below were taken at Port Washington's own scale — its own ~209-day season between 28°F freezes, the 3,811 acres it covers and 622 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Port Washington's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Port Washington's own 28°F hard-freeze dates, about Apr 10 and Nov 5 and the ~209-day span between themNOAA 1991–2020 Climate Normals
- 622 documented contamination sites on the federal record near Port Washington, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Port Washington's boundary and the 3,811 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~209-day seasonGrowable Ground crop-matching engine
- The ecoregion at Port Washington's own centroid, the Southeastern Wisconsin Till PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Port Washington's 3,811 acres read through its county's SSURGO summaryfrom Ozaukee County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Ozaukee County
- The growing challenges every Wisconsin grower plans around — written at state scale, so they stay on the state guidefrom Wisconsin
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Ozaukee County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Port Washington's 3,811 acreswhy one lot differs from the next →
- Which side of Port Washington you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,811 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 Port Washington-wide figureread your own land →