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

Planting zone for 95966 — Oroville, CA

ZIP code 95966 (Oroville, Butte County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is January 30 and the first fall frost December 13.

Where ZIP 95966 is

Outlined: the ZIP code area · 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
Coldest night−3.9 to −1.1 °C
Last frostJan 30
First frostDec 13
2012 zone9b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9b means →

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 — 8 miles away, 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 95966

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 95966 came on Jan 28 — 4 days earlier than the 1991–2020 average (Feb 1).

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 95966 is Sommeyflat — loam, well drained.

TextureLoama good balance for most vegetables
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter5%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Sommeyflat-Mounthope-Hurleton , 30 to 50 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 95966; 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 57 mindaylight on June 21
Shortest day9 h 23 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation33.1 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″2″4″6″January: 5.22 in precipitation 5.2 JanFebruary: 6.43 in precipitation 6.4 FebMarch: 4.75 in precipitation 4.8 MarApril: 2.10 in precipitation 2.1 AprMay: 2.14 in precipitation 2.1 MayJune: 0.54 in precipitation 0.5 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.10 in precipitation 0.1 AugSeptember: 0.22 in precipitation 0.2 SepOctober: 1.83 in precipitation 1.8 OctNovember: 3.39 in precipitation 3.4 NovDecember: 6.35 in precipitation 6.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oroville, CA (8 mi away); precipitation: Palermo 2.7 Se, CA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

959149b
Bangor, CA · 5 mi
959729b
Rackerby, CA · 5 mi
959689b
Palermo, CA · 8 mi
959419a
Forbestown, CA · 8 mi
959199a
Brownsville, CA · 8 mi
959259a
Challenge, CA · 12 mi
959659b
Oroville, CA · 12 mi
959169b
Berry Creek, CA · 12 mi

All 2 ZIP codes in Oroville → · California planting zones →

Questions about 95966

What planting zone is ZIP code 95966?

ZIP code 95966 (Oroville, CA) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Oroville, CA?

The median last spring frost (32 °F) near 95966 is January 30; after March 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Oroville station.

When is the first frost in Oroville, CA?

The median first fall frost near 95966 is December 13, giving a median frost-free growing season of 321 days.

When should I plant tomatoes in 95966?

Start tomato seeds indoors around Dec 5 – Dec 19 and set transplants outside around Feb 6 – Feb 20, one to three weeks after the median last frost.

How much rain and snow does 95966 get?

About 33.1 inches of precipitation a year (NOAA 1991–2020 normals, Palermo 2.7 Se station).

How hot do summers get in Oroville, CA?

The average high peaks at 97 °F in July, with about 97 days a year at 90 °F or more.

What kind of soil does 95966 have?

The USDA soil survey maps Sommeyflat at the center of ZIP 95966: loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Oroville, CA in 2026?

Spring leaf-out near 95966 came on Jan 28 in 2026, 4 days earlier than the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Oroville, CA?

Intermediate onions: the longest day near 95966 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.