Guerneville, California, sits in USDA hardiness zone 9b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Crops well matched to these conditions include okra, meyer lemon, california poppy, and artichoke — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Guerneville, 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 Guerneville 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 Guerneville — soil, climate, flood, and parcel records. How we handle your address.
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Guerneville — the short answer
Guerneville, California: USDA zone 9b, about 323 days between hard freezes, across 6K acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 23
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 12
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~323
- Sonoma County normal — NOAA 1991–2020, nearest to this town
- Town area
- 6K 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 Sonoma County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Guerneville's average, not your lot's — a low corner or a tree line moves it. Against Guerneville's 323-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Guerneville
Each reading below is measured for Guerneville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsGuerneville runs about 323 days between hard freezes (read from Sonoma County, the closest normal to Guerneville) — 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
MeasuredGuerneville 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 Guerneville is in
Guerneville sits in the Coast Range — EPA Level III, inside the wider Marine West Coast Forest. That is read at Guerneville's own centroid, and it is not what its county reads: Sonoma County is mostly Central California Foothills and Coastal Mountains. The wider page above you is answering a different question about different ground.
What Grows in Guerneville
Every plant below cleared Guerneville's own zone 9b and its 323-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Guerneville?
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 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 12 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
What's on the federal record near Guerneville
Closest first, within ~10 miles of Guerneville. Listing isn't leaking, and distance isn't exposure.
- SONOMA COUNTY WASTE MANAGEMENT AGENCYBrownfields · 1900 ft
- SOCO ROAD YARD - GUERNEVILLEBrownfields · 2200 ft
- MD Gas & FOOD #13Underground Storage Tanks · 2400 ft
- JHHD CORP DBA MD GAS & FOOD #13Brownfields · 2500 ft
- GEORGE WHITEBrownfields · 0.5 mi
- 008N010W29H004MNitrate · 0.6 mi
- STEVES FOREIGN AUTOBrownfields · 1.1 mi
- RUSSIAN RIVER FLOODSuperfund · 1.1 mi
- JIM LONG'S POWER PRODUCTSBrownfields · 1.1 mi
- SWEETWATER SPRINGS CWD - GUERNEVILLEPFAS · 1.1 mi
- PACIFIC BELLBrownfields · 1.2 mi
- CALIFORNIA STATE PARKS ARMSTRONG REDWOODS SNRBrownfields · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Guerneville'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 Guerneville.
Total Sites
389
within ~10 miles of Guerneville
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Guerneville
Severity Distribution
within ~10 miles of Guerneville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Guerneville, two things run higher than the national average within ~10 miles of Guerneville — Mining (48 sites) and PFAS (5 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.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Guerneville
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 Guerneville average
Your land is one point inside Guerneville
Everything above resolves to Guerneville as a whole — one PHZM band, read across 6K acres, with hard-freeze dates borrowed from Sonoma County’s record because no 30-year normal resolves at this town’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 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 Guerneville Average
Guerneville Average
- ●USDA Zones 9b, averaged across Guerneville
- ●One soil character for all of Guerneville
- ●Frost dates read at Guerneville's scale: Jan 23 to Dec 12
YOUR Parcel
- ✓Your exact zone, not Guerneville's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Guerneville
Pull a site-specific report for your exact address in Guerneville, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Guerneville averages can't show:
We read public map data around Guerneville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Guerneville average
How we know this about Guerneville
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 Sonoma 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 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 Guerneville
When does frost risk typically end in Guerneville?
The last hard freeze (28°F) in Guerneville typically lands around Jan 23, 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 13.
When is the first frost in Guerneville?
The first hard freeze (28°F) in Guerneville typically arrives around Dec 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 28, so the watching starts about Nov 12 — about 323 days after the spring freeze cleared.
How long is the growing season in Guerneville?
Measured between 28°F hard freezes, Guerneville sees about 323 frost-free days — roughly Jan 23 through Dec 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 13 to Nov 28, about 288 days.
Is the soil safe to grow vegetables in Guerneville?
The federal record around Guerneville is a meaningful one — 389 documented sites, mostly Brownfields entries (256), the nearest Brownfields record about 0.4 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 Guerneville?
From about Nov 12 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Guerneville's scale — its 9b band and its 323-day season. Your yard writes its own version of Guerneville'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 Guerneville’s own scale
5 of the readings below were taken at Guerneville's own scale — the 6,214 acres it covers and 389 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Guerneville's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 389 documented contamination sites on the federal record near Guerneville, the closest Brownfields record about 0.4 miles out from the town centreFederal environmental registers
- Guerneville's boundary and the 6,214 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~323-day seasonGrowable Ground crop-matching engine
- Guerneville sits in the Coast Range — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Guerneville has no normal of its own, so its county's is the closest measured readfrom Sonoma County
- Soil character — no town-scale survey exists, so Guerneville's 6,214 acres read through its county's SSURGO summaryfrom Sonoma County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Sonoma 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 Sonoma County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Guerneville's 6,214 acreswhy one lot differs from the next →
- Which side of Guerneville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,214 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.4 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 Guerneville-wide figureread your own land →
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