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

Planting zone for 95497 — The Sea Ranch, CA

ZIP code 95497 (The Sea Ranch, Sonoma County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F. The median last spring frost is February 26 and the first fall frost December 27.

Where ZIP 95497 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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostFeb 26
First frostDec 27
2012 zone9b

Was 9b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for The Sea Ranch, 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 The Sea Ranch, 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 — 19 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 95497

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 95497 came on Jan 27 — about the same time as the 1991–2020 average (Jan 28).

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 The Sea Ranch, CA

The soil mapped at the center of ZIP 95497 is Caspar — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Caspar sandy loam, 15 to 30 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 95497; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in The Sea Ranch, 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 53 mindaylight on June 21
Shortest day9 h 27 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation39.2 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″January: 7.18 in precipitation 7.2 JanFebruary: 6.95 in precipitation 7.0 FebMarch: 5.15 in precipitation 5.2 MarApril: 2.88 in precipitation 2.9 AprMay: 1.60 in precipitation 1.6 MayJune: 0.48 in precipitation 0.5 JunJuly: 0.04 in precipitation 0.0 JulAugust: 0.07 in precipitation 0.1 AugSeptember: 0.17 in precipitation 0.2 SepOctober: 1.97 in precipitation 2.0 OctNovember: 4.24 in precipitation 4.2 NovDecember: 8.44 in precipitation 8.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ft Ross, CA (19 mi away); precipitation: Ft Ross, CA (19 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

9548010a
Stewarts Point, CA · 6 mi
954459b
Gualala, CA · 7 mi
954129b
Annapolis, CA · 8 mi
954949b
Yorkville, CA · 13 mi
954689b
Point Arena, CA · 16 mi
954219b
Cazadero, CA · 18 mi
954599b
Manchester, CA · 19 mi
9545010a
Jenner, CA · 20 mi

California planting zones →

Questions about 95497

What planting zone is ZIP code 95497?

ZIP code 95497 (The Sea Ranch, CA) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

When is the last frost in The Sea Ranch, CA?

The median last spring frost (32 °F) near 95497 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 The Sea Ranch, CA?

The median first fall frost near 95497 is December 27, giving a median frost-free growing season of 310 days.

When should I plant tomatoes in 95497?

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 95497 get?

About 39.2 inches of precipitation a year (NOAA 1991–2020 normals, Ft Ross station).

How hot do summers get in The Sea Ranch, 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 95497 have?

The USDA soil survey maps Caspar at the center of ZIP 95497: sandy loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in The Sea Ranch, CA in 2026?

Spring leaf-out near 95497 came on Jan 27 in 2026, about the same as the 1991–2020 average (Jan 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in The Sea Ranch, CA?

Intermediate onions: the longest day near 95497 is 14 h 53 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 95497 change?

Yes. The 2012 USDA map put 95497 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.