Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for Oroville, CA

Oroville, CA is in USDA zone 9b across its 2 ZIP codes. The median last spring frost is January 30 and the first fall frost December 13.

Oroville on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone9b25 to 30 °F
ZIP codes2
Last frostJan 30
First frostDec 13
Growing season321 days

9b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Oroville, CA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Oroville, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 30median — 50% chance of a later frost
Safe for tender plantsMarch 3only 10% chance of frost after
First fall frostDecember 13median — 10% chance by Nov 21
Growing season321 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 5 and returns around December 25.

From the NOAA station Oroville, CA, elevation 171 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Oroville

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 19 – Jan 2
SpinachSow outdoors · Dec 19 – Jan 9
Broccoli, cabbageStart indoors · Nov 21 – Dec 5
Broccoli, cabbageTransplant · Jan 9 – Jan 23
Onion setsPlant outdoors · Jan 2 – Jan 16
PotatoesPlant outdoors · Jan 9 – Jan 23
LettuceSow outdoors · Jan 2 – Jan 16
Carrots, beetsSow outdoors · Jan 9 – Jan 23
TomatoesStart indoors · Dec 5 – Dec 19
TomatoesTransplant · Feb 6 – Feb 20
Peppers, eggplantStart indoors · Nov 21 – Dec 5
Peppers, eggplantTransplant · Feb 13 – Feb 27
BeansSow outdoors · Feb 6 – Feb 20
Sweet cornSow outdoors · Feb 6 – Feb 20
Cucumbers, squashSow outdoors · Feb 6 – Feb 20
Fall lettuce, spinachSow outdoors · Oct 18 – Nov 1
GarlicPlant cloves · Nov 29 – Jan 3
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 30) and first fall frost (Dec 13) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 95965 came on Jan 27 — 4 days earlier than the 1991–2020 average (Jan 31).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Oroville, CA

The soil mapped at the center of ZIP 95965 is Cherotable — loam, moderately well drained.

TextureLoama good balance for most vegetables
pH4.8strongly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter10.6%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Cherotable-Elsey , 2 to 15 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 95965; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oroville, CA

Summer high97 °Faverage high, July
Winter low40 °Faverage low, January
Hot days97days a year at 90 °F or more
Freezing nights16nights a year at 32 °F or less
Growing degree days5,179base 50 °F — the season’s usable heat
Longest day14 h 58 mindaylight on June 21
Shortest day9 h 22 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation30.6 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 58 °F, low 40 °F 58°40° JanFebruary: average high 62 °F, low 42 °F 62°42° FebMarch: average high 68 °F, low 46 °F 68°46° MarApril: average high 74 °F, low 48 °F 74°48° AprMay: average high 82 °F, low 54 °F 82°54° MayJune: average high 91 °F, low 59 °F 91°59° JunJuly: average high 97 °F, low 63 °F 97°63° JulAugust: average high 96 °F, low 61 °F 96°61° AugSeptember: average high 90 °F, low 57 °F 90°57° SepOctober: average high 79 °F, low 51 °F 79°51° OctNovember: average high 66 °F, low 45 °F 66°45° NovDecember: average high 58 °F, low 40 °F 58°40° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.79 in precipitation 5.8 JanFebruary: 5.62 in precipitation 5.6 FebMarch: 4.71 in precipitation 4.7 MarApril: 2.23 in precipitation 2.2 AprMay: 1.43 in precipitation 1.4 MayJune: 0.59 in precipitation 0.6 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.13 in precipitation 0.1 AugSeptember: 0.37 in precipitation 0.4 SepOctober: 1.33 in precipitation 1.3 OctNovember: 2.85 in precipitation 2.9 NovDecember: 5.50 in precipitation 5.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oroville, CA (6 mi away); precipitation: Oroville, CA (6 mi away). Daylight is calculated from latitude.

ZIP codes in Oroville

959659b
25 to 30 °F
959669b
25 to 30 °F

California planting zones →

Questions about Oroville

What planting zone is Oroville, CA?

Oroville, CA is in USDA hardiness zone 9b on the 2023 map (9b: 25 to 30 °F).

When is the last frost in Oroville, CA?

The median last spring frost is January 30 and the median first fall frost is December 13 (NOAA 1991–2020 normals, Oroville station).

When can I plant a garden in Oroville, CA?

Cool-season crops like peas and spinach go in around Dec 19 – Jan 9; tomatoes, peppers, beans and squash after about Feb 6, once frost risk has passed.

What kind of onions grow in Oroville, CA?

Intermediate onions: the longest day is 14 h 58 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Oroville, CA get?

About 30.6 inches of precipitation a year (NOAA 1991–2020 normals).