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

Planting zone for 95421 — Cazadero, CA

ZIP code 95421 (Cazadero, Sonoma County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 26 and the first fall frost December 27.

Where ZIP 95421 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 frostFeb 26
First frostDec 27
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 Cazadero, 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 Cazadero, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 26median — 50% chance of a later frost
Safe for tender plantsMay 1only 10% chance of frost after
First fall frostDecember 27median — 10% chance by Dec 1
Growing season310 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 29 and returns around January 16.

From the NOAA station Ft Ross, CA — 6 miles away, elevation 112 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 95421

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 15 – Jan 29
SpinachSow outdoors · Jan 15 – Feb 5
Broccoli, cabbageStart indoors · Dec 18 – Jan 1
Broccoli, cabbageTransplant · Feb 5 – Feb 19
Onion setsPlant outdoors · Jan 29 – Feb 12
PotatoesPlant outdoors · Feb 5 – Feb 19
LettuceSow outdoors · Jan 29 – Feb 12
Carrots, beetsSow outdoors · Feb 5 – Feb 19
TomatoesStart indoors · Jan 1 – Jan 15
TomatoesTransplant · Mar 5 – Mar 19
Peppers, eggplantStart indoors · Dec 18 – Jan 1
Peppers, eggplantTransplant · Mar 12 – Mar 26
BeansSow outdoors · Mar 5 – Mar 19
Sweet cornSow outdoors · Mar 5 – Mar 19
Cucumbers, squashSow outdoors · Mar 5 – Mar 19
Fall lettuce, spinachSow outdoors · Nov 1 – Nov 15
GarlicPlant cloves · Dec 13 – Jan 17
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 26) and first fall frost (Dec 27) 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 95421 came on Jan 20 — 10 days earlier than the 1991–2020 average (Jan 30).

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 Cazadero, CA

The soil mapped at the center of ZIP 95421 is Hugo — very gravelly loam, well drained.

TextureVery gravelly loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter4%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Hugo very gravelly loam, 50 to 75 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 95421; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cazadero, CA

Summer high67 °Faverage high, August
Winter low42 °Faverage low, January
Hot days0days a year at 90 °F or more
Freezing nights12nights a year at 32 °F or less
Growing degree days1,555base 50 °F — the season’s usable heat
Longest day14 h 52 mindaylight on June 21
Shortest day9 h 28 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation64.2 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 57 °F, low 42 °F 57°42° JanFebruary: average high 59 °F, low 42 °F 59°42° FebMarch: average high 59 °F, low 42 °F 59°42° MarApril: average high 60 °F, low 43 °F 60°43° AprMay: average high 62 °F, low 45 °F 62°45° MayJune: average high 66 °F, low 46 °F 66°46° JunJuly: average high 66 °F, low 48 °F 66°48° JulAugust: average high 67 °F, low 50 °F 67°50° AugSeptember: average high 67 °F, low 48 °F 67°48° SepOctober: average high 66 °F, low 47 °F 66°47° OctNovember: average high 61 °F, low 44 °F 61°44° NovDecember: average high 57 °F, low 42 °F 57°42° Dec

Precipitation by month inches

0″2″4″6″8″10″12″January: 11.63 in precipitation 11.6 JanFebruary: 11.89 in precipitation 11.9 FebMarch: 9.95 in precipitation 9.9 MarApril: 3.50 in precipitation 3.5 AprMay: 3.63 in precipitation 3.6 MayJune: 0.68 in precipitation 0.7 JunJuly: 0.03 in precipitation 0.0 JulAugust: 0.06 in precipitation 0.1 AugSeptember: 0.42 in precipitation 0.4 SepOctober: 3.16 in precipitation 3.2 OctNovember: 7.06 in precipitation 7.1 NovDecember: 12.14 in precipitation 12.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ft Ross, CA (6 mi away); precipitation: Cazadero 5.6 W, CA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

9545010a
Jenner, CA · 5 mi
954469b
Guerneville, CA · 10 mi
954309b
Duncans Mills, CA · 11 mi
954129b
Annapolis, CA · 11 mi
954869b
Villa Grande, CA · 11 mi
954629b
Monte Rio, CA · 12 mi
954719b
Rio Nido, CA · 12 mi
954419b
Geyserville, CA · 12 mi

California planting zones →

Questions about 95421

What planting zone is ZIP code 95421?

ZIP code 95421 (Cazadero, 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 Cazadero, CA?

The median last spring frost (32 °F) near 95421 is February 26; after May 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ft Ross station.

When is the first frost in Cazadero, CA?

The median first fall frost near 95421 is December 27, giving a median frost-free growing season of 310 days.

When should I plant tomatoes in 95421?

Start tomato seeds indoors around Jan 1 – Jan 15 and set transplants outside around Mar 5 – Mar 19, one to three weeks after the median last frost.

How much rain and snow does 95421 get?

About 64.2 inches of precipitation a year (NOAA 1991–2020 normals, Cazadero 5.6 W station).

How hot do summers get in Cazadero, CA?

The average high peaks at 67 °F in August, with about 0 days a year at 90 °F or more.

What kind of soil does 95421 have?

The USDA soil survey maps Hugo at the center of ZIP 95421: very gravelly loam, well drained, pH about 6.5 (neutral).

Did spring come early in Cazadero, CA in 2026?

Spring leaf-out near 95421 came on Jan 20 in 2026, 10 days earlier than the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cazadero, CA?

Intermediate onions: the longest day near 95421 is 14 h 52 min, so day-neutral types bulb best; long-day varieties may not bulb fully.