Williams, California, sits in USDA hardiness zone 9b — a zone band wide enough that plant choice, not possibility, is the interesting question.
A short list that earns its place here — okra, meyer lemon, california poppy, and artichoke — with any one site's soil, sun, and drainage making the final cut.
Even in Williams, 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 Williams 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 Williams — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Williams — the short answer
Williams, California: USDA zone 9b, about 329 days between hard freezes, across 3K acres of city.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 19
- Colusa County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 14
- Colusa County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~329
- Colusa County normal — NOAA 1991–2020, nearest to this town
- City area
- 3K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Colusa County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Williams's average, not your lot's — a low corner or a tree line moves it. Against Williams's 329-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Williams
Each reading below is measured for Williams itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsWilliams runs about 329 days between hard freezes (read from Colusa County, the closest normal to Williams) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredWilliams sits in USDA hardiness zone 9b.
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 Williams is in
Williams sits in the Central California Valley — EPA Level III, inside the wider Mediterranean California. That is read at Williams's own centroid rather than borrowed from Colusa County.
What Grows in Williams
Every plant below cleared Williams's own zone 9b and its 329-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Williams?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 14 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
What's on the federal record near Williams
Closest first, within ~10 miles of Williams. Listing isn't leaking, and distance isn't exposure.
- SEMINIS VEGETABLE SEEDS, INC.Brownfields · 550 ft
- 015N003W13Q001MNitrate · 950 ft
- BAR ALE, INC.Brownfields · 1200 ft
- KELLY ORNBAUN DBA FARMINGBrownfields · 1800 ft
- TIM INGRAHAM TRUCKINGBrownfields · 1900 ft
- HERNANDEZ TRUCKINGBrownfields · 1900 ft
- HALLIBURTON SERVBrownfields · 1900 ft
- 015N002W18M001MNitrate · 2000 ft
- PETERSON EQUIPMENT TRUSTBrownfields · 2000 ft
- GLENN COLUSA IRRIGATION DISTBrownfields · 2000 ft
- SANDERS HEAVY TOWINGBrownfields · 2100 ft
- WILLIAMS SINCLAIRUnderground Storage Tanks · 2300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Williams'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 Williams.
Total Sites
347
within ~10 miles of Williams
Risk Level
Elevated
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Williams
Severity Distribution
within ~10 miles of Williams
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Williams, two things run higher than the national average within ~10 miles of Williams — Nitrate (168 sites) and PFAS (3 sites). 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.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Williams
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 Williams average
Your land is one point inside Williams
Everything above resolves to Williams as a whole — one PHZM band, read across 3K acres, with hard-freeze dates borrowed from Colusa County’s record because no 30-year normal resolves at this city’s own centroid. 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 Williams Average
Williams Average
- ●USDA Zones 9b, averaged across Williams
- ●One soil character for all of Williams
- ●Frost dates read at Williams's scale: Jan 19 to Dec 14
YOUR Parcel
- ✓Your exact zone, not Williams's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Williams
Pull a site-specific report for your exact address in Williams, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Williams averages can't show:
We read public map data around Williams — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Williams average
How we know this about Williams
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 Colusa County’s record, because none resolves here; 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 Williams
When does frost risk typically end in Williams?
The last hard freeze (28°F) in Williams typically lands around Jan 19, 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 Feb 9.
When is the first frost in Williams?
The first hard freeze (28°F) in Williams typically arrives around Dec 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 30, so the watching starts about Nov 14 — about 329 days after the spring freeze cleared.
How long is the growing season in Williams?
Measured between 28°F hard freezes, Williams sees about 329 frost-free days — roughly Jan 19 through Dec 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 9 to Nov 30, about 294 days.
Is the soil safe to grow vegetables in Williams?
The federal record around Williams is a meaningful one — 347 documented sites, mostly Nitrate entries (168), the nearest Brownfields record about 0.1 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 Williams?
From about Nov 14 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 Dec 14 (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 Dec 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Williams's scale — its 9b band and its 329-day season. Your yard writes its own version of Williams'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 Williams’s own scale
5 of the readings below were taken at Williams's own scale — the 3,165 acres it covers and 347 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Williams's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 347 documented contamination sites on the federal record near Williams, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Williams's boundary and the 3,165 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~329-day seasonGrowable Ground crop-matching engine
- The ecoregion at Williams's own centroid, the Central California ValleyUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Williams has no normal of its own, so its county's is the closest measured readfrom Colusa County
- Soil character — no town-scale survey exists, so Williams's 3,165 acres read through its county's SSURGO summaryfrom Colusa County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Colusa 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 Colusa County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Williams's 3,165 acreswhy one lot differs from the next →
- Which side of Williams you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,165 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.1 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 Williams-wide figureread your own land →