Douglas City, California, sits in USDA hardiness zone 8b — 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, fig, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Douglas 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 Douglas 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 Douglas City — soil, climate, flood, and parcel records. How we handle your address.
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Douglas City — the short answer
Douglas City, California: USDA zone 8b, about 247 days between hard freezes, across 19K acres of town.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~247
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 19K 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 8b is Douglas City's average, not your lot's — a low corner or a tree line moves it. Against Douglas City's 247-day season, see what your own ground reads.
Your town runs its own season
Douglas City's own 30-year record measures about 247 days between 28°F killing freezes — 43 days longer than Trinity County's ~204. Both are measured records, not estimates.
That gap is the whole reason a county average can mislead here. Plant against Douglas City's ~247-day season rather than the county figure — and the sun, slope and cold-air drainage on your specific lot move it again.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record. Both figures are measured records — this town’s own and its county’s. A town with no record of its own is absent here rather than estimated.
Soil varies lot by lot — soil types explained.
What this means for growing in Douglas City
Each reading below is measured for Douglas City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDouglas City runs about 247 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
MeasuredDouglas City sits in USDA hardiness zone 8b.
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 Douglas City is in
Douglas City sits in the Klamath Mountains/California High North Coast Range — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Douglas City's own centroid rather than borrowed from Trinity County.
What Grows in Douglas City
Every plant below cleared Douglas City's own zone 8b and its 247-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Douglas City?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 20 — 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 Douglas City
Closest first, within ~10 miles of Douglas City. Listing isn't leaking, and distance isn't exposure.
- CALTRANS DOUGLAS CITY SITEBrownfields · 0.7 mi
- CHEEK SKYLINE LOGGINGSuperfund · 3.4 mi
- Dixie QueenMining · 4.2 mi
- Democrat GroupMining · 4.5 mi
- TRINITY COUNTY PUBLIC HEALTH DEPTBrownfields · 4.5 mi
- TRINITY PUBLIC UTILITIES DISTRICTBrownfields · 4.7 mi
- LAUDERDALE MOTORSBrownfields · 4.8 mi
- UnnamedMining · 4.9 mi
- HOLIDAY MARKETBrownfields · 5.2 mi
- WESTERN MINERALS EXPLORATION LTDBrownfields · 5.2 mi
- CVS PHARMACY #9973Brownfields · 5.3 mi
- OWENS HEALTHCARE #18Brownfields · 5.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Douglas 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 Douglas City.
Total Sites
71
within ~10 miles of Douglas City
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Douglas City
Severity Distribution
within ~10 miles of Douglas City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Douglas City, two things run higher than the national average within ~10 miles of Douglas City — Mining (11 sites) and Brownfields (46 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Douglas 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 Douglas City average
Your land is one point inside Douglas City
Everything above resolves to Douglas City as a whole — and this is a town whose own 30-year record already runs a season its county’s does not. Your parcel sits at one point inside even that. 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 Douglas City Average
Douglas City Average
- ●USDA Zones 8b, averaged across Douglas City
- ●One soil character for all of Douglas City
- ●Frost dates read at Douglas City's scale: Mar 18 to Nov 20
YOUR Parcel
- ✓Your exact zone, not Douglas City's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Douglas City
Pull a site-specific report for your exact address in Douglas City, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Douglas City averages can't show:
We read public map data around Douglas City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Douglas City average
How we know this about Douglas 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 Douglas 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 Douglas City
When does frost risk typically end in Douglas City?
The last hard freeze (28°F) in Douglas City typically lands around Mar 18, 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 8.
When is the first frost in Douglas City?
The first hard freeze (28°F) in Douglas City typically arrives around Nov 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 6, so the watching starts about Oct 21 — about 247 days after the spring freeze cleared.
How long is the growing season in Douglas City?
Measured between 28°F hard freezes, Douglas City sees about 247 frost-free days — roughly Mar 18 through Nov 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 8 to Nov 6, about 212 days.
Is the soil safe to grow vegetables in Douglas City?
The federal record around Douglas City is a meaningful one — 71 documented sites, mostly Brownfields entries (46), the nearest Brownfields record about 0.7 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 Douglas City?
From about Oct 21 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 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Douglas City's scale — its 8b band and its 247-day season. Your yard writes its own version of Douglas 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 Douglas City’s own scale
6 of the readings below were taken at Douglas City's own scale — its own ~247-day season between 28°F freezes, the 19,472 acres it covers and 71 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Douglas City's own USDA hardiness band, zones 8bUSDA PHZM 2023
- Douglas City's own 28°F hard-freeze dates, about Mar 18 and Nov 20 and the ~247-day span between themNOAA 1991–2020 Climate Normals
- 71 documented contamination sites on the federal record near Douglas City, the closest Brownfields record about 0.7 miles out from the town centreFederal environmental registers
- Douglas City's boundary and the 19,472 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~247-day seasonGrowable Ground crop-matching engine
- The ecoregion at Douglas City's own centroid, the Klamath Mountains/California High North Coast RangeUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Douglas City's 19,472 acres read through its county's SSURGO summaryfrom Trinity County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Trinity County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Trinity County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Douglas City's 19,472 acreswhy one lot differs from the next →
- Which side of Douglas 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 19,472 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.7 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 Douglas City-wide figureread your own land →
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