Oroville, California, sits in USDA hardiness zone 9b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include okra, meyer lemon, california poppy, and artichoke; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Oroville, 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 Oroville 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 Oroville — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Oroville — the short answer
Oroville, California: USDA zone 9b, about 332 days between hard freezes, across 9K acres of city.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 19
- Butte County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 17
- Butte County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~332
- Butte County normal — NOAA 1991–2020, nearest to this town
- City area
- 9K 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 Butte County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Oroville's average, not your lot's — a low corner or a tree line moves it. Against Oroville's 332-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Oroville
Each reading below is measured for Oroville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsOroville runs about 332 days between hard freezes (read from Butte County, the closest normal to Oroville) — 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
MeasuredOroville 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 Oroville is in
Oroville sits in the Central California Valley — EPA Level III, inside the wider Mediterranean California. That is read at Oroville's own centroid rather than borrowed from Butte County.
What Grows in Oroville
Every plant below cleared Oroville's own zone 9b and its 332-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Oroville?
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 17 — 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 Oroville
Closest first, within ~10 miles of Oroville. Listing isn't leaking, and distance isn't exposure.
- FEDEX GROUND PACKAGE SYSTEM INCBrownfields · 650 ft
- SHIFFLET BROS ENTERPRISES INCBrownfields · 900 ft
- TRINITY RIVER LUMBER COMPANY-LOG STORAGE & RELOAD FACILITYBrownfields · 1000 ft
- OROVILLE COGENERATION LPBrownfields · 1300 ft
- DAWSON OIL COMPANY - OROVILLE CARDLOCKBrownfields · 1400 ft
- S & T LOGGINGBrownfields · 1500 ft
- DBA FAIRBANKS PAVING COBrownfields · 1600 ft
- WRIGHT PRECISION INCBrownfields · 1700 ft
- KING TOWINGBrownfields · 1700 ft
- NORCAL RENTAL GROUP LLC DBA CRESCO EQUPIMENT RENTALSBrownfields · 1900 ft
- 5TH AVE BOSY SHOPBrownfields · 1900 ft
- RECOLOGY BUTTE COLUSA COUNTIESBrownfields · 1900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Oroville'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 Oroville.
Sources Checked
within ~10 miles of Oroville
Severity Distribution
within ~10 miles of Oroville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Oroville, two things run higher than the national average within ~10 miles of Oroville — Brownfields (257 sites) and PFAS (4 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Oroville
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 Oroville average
Your land is one point inside Oroville
Everything above resolves to Oroville as a whole — one PHZM band, read across 9K acres, with hard-freeze dates borrowed from Butte 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 Oroville Average
Oroville Average
- ●USDA Zones 9b, averaged across Oroville
- ●One soil character for all of Oroville
- ●Frost dates read at Oroville's scale: Jan 19 to Dec 17
YOUR Parcel
- ✓Your exact zone, not Oroville's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Oroville
Pull a site-specific report for your exact address in Oroville, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Oroville averages can't show:
We read public map data around Oroville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Oroville average
How we know this about Oroville
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 Butte 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 Oroville
When does frost risk typically end in Oroville?
The last hard freeze (28°F) in Oroville 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 Oroville?
The first hard freeze (28°F) in Oroville typically arrives around Dec 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 3, so the watching starts about Nov 17 — about 332 days after the spring freeze cleared.
How long is the growing season in Oroville?
Measured between 28°F hard freezes, Oroville sees about 332 frost-free days — roughly Jan 19 through Dec 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 9 to Dec 3, about 297 days.
Is the soil safe to grow vegetables in Oroville?
The federal record around Oroville runs heavier than most — 403 documented sites, mostly Brownfields entries (257), the nearest Brownfields record about 0.1 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Oroville?
From about Nov 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Oroville's scale — its 9b band and its 332-day season. Your yard writes its own version of Oroville'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 Oroville’s own scale
5 of the readings below were taken at Oroville's own scale — the 8,895 acres it covers and 403 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Oroville's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 403 documented contamination sites on the federal record near Oroville, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Oroville's boundary and the 8,895 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~332-day seasonGrowable Ground crop-matching engine
- The ecoregion at Oroville's own centroid, the Central California ValleyUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Oroville has no normal of its own, so its county's is the closest measured readfrom Butte County
- Soil character — no town-scale survey exists, so Oroville's 8,895 acres read through its county's SSURGO summaryfrom Butte County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Butte 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 Butte County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Oroville's 8,895 acreswhy one lot differs from the next →
- Which side of Oroville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 8,895 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 Oroville-wide figureread your own land →
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