Coulee City, Washington, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, pawpaw, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Coulee City, 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 Coulee City 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 Coulee City — soil, climate, flood, and parcel records. How we handle your address.
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Coulee City — the short answer
Coulee City, Washington: USDA zone 7a, about 208 days between hard freezes, across 591 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~208
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 591 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 7a is Coulee City's average, not your lot's — a low corner or a tree line moves it. Against Coulee City's 208-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Coulee City
Each reading below is measured for Coulee City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCoulee City runs about 208 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
MeasuredCoulee City sits in USDA hardiness zone 7a.
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 Coulee City is in
Coulee City sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Coulee City's own centroid rather than borrowed from Grant County.
What Grows in Coulee City
Every plant below cleared Coulee City's own zone 7a and its 208-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Coulee City?
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 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 29 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Coulee City
Closest first, within ~10 miles of Coulee City. Listing isn't leaking, and distance isn't exposure.
- COULEE HARTLINE SCHOOL DISTRICT 151Underground Storage Tanks · 1100 ft
- FULLER AUTO SALESUnderground Storage Tanks · 1900 ft
- DAVID N MAJOR MAJOR OIL COUnderground Storage Tanks · 0.7 mi
- WA DOT COULEE CITY MAINTENANCEUnderground Storage Tanks · 0.9 mi
- ISAAK BROTHERSUnderground Storage Tanks · 0.9 mi
- JESSE B KNOPPUnderground Storage Tanks · 1.1 mi
- WESTERN FARM SERVICE INC COULEE CITYUnderground Storage Tanks · 1.3 mi
- CROP PRODUCTION SERVICES COULEE CITYBrownfields · 1.3 mi
- FRONTIER CORNERUnderground Storage Tanks · 2.2 mi
- FULLER DRY FALLS MINI-MARTUnderground Storage Tanks · 2.3 mi
- RESERVOIR CAFEUnderground Storage Tanks · 4.7 mi
- SUN LAKES STATE PARKUnderground Storage Tanks · 5.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Coulee City'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 Coulee City.
Sources Checked
within ~10 miles of Coulee City
Severity Distribution
within ~10 miles of Coulee City
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Coulee City
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 Coulee City average
Your land is one point inside Coulee City
Everything above resolves to Coulee City as a whole — one PHZM band and one 28°F frost record, read across 591 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 Coulee City Average
Coulee City Average
- ●USDA Zones 7a, averaged across Coulee City
- ●One soil character for all of Coulee City
- ●Frost dates read at Coulee City's scale: Apr 4 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Coulee City's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Coulee City
Pull a site-specific report for your exact address in Coulee City, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Coulee City averages can't show:
We read public map data around Coulee City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Coulee City average
How we know this about Coulee City
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 Coulee City’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 Coulee City
When does frost risk typically end in Coulee City?
The last hard freeze (28°F) in Coulee City typically lands around Apr 4, 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 25.
When is the first frost in Coulee City?
The first hard freeze (28°F) in Coulee City typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 208 days after the spring freeze cleared.
How long is the growing season in Coulee City?
Measured between 28°F hard freezes, Coulee City sees about 208 frost-free days — roughly Apr 4 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 25 to Oct 15, about 173 days.
Is the soil safe to grow vegetables in Coulee City?
The federal record around Coulee City is light — 20 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (16), the nearest Underground Storage Tanks record about 0.2 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Coulee City?
From about Sep 29 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 29 (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 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Coulee City's scale — its 7a band and its 208-day season. Your yard writes its own version of Coulee City'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 Coulee City’s own scale
6 of the readings below were taken at Coulee City's own scale — its own ~208-day season between 28°F freezes, the 591 acres it covers and 20 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Coulee City's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Coulee City's own 28°F hard-freeze dates, about Apr 4 and Oct 29 and the ~208-day span between themNOAA 1991–2020 Climate Normals
- 20 documented contamination sites on the federal record near Coulee City, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Coulee City's boundary and the 591 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~208-day seasonGrowable Ground crop-matching engine
- The ecoregion at Coulee City's own centroid, the Columbia PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Coulee City's 591 acres read through its county's SSURGO summaryfrom Grant County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Grant 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 Grant County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Coulee City's 591 acreswhy one lot differs from the next →
- Which side of Coulee City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 591 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Coulee City-wide figureread your own land →
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