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

Planting zone for 95979 — Stonyford, CA

ZIP code 95979 (Stonyford, Colusa County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is April 6 and the first fall frost November 10.

Where ZIP 95979 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.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostApr 6
First frostNov 10
2012 zone8b

Was 8b 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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Stonyford, 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 Stonyford, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 6median — 50% chance of a later frost
Safe for tender plantsApril 25only 10% chance of frost after
First fall frostNovember 10median — 10% chance by Oct 27
Growing season219 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 2 and returns around November 24.

From the NOAA station East Park Rsvr, CA — 5 miles away, elevation 1,204 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 95979

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 23 – Mar 9
SpinachSow outdoors · Feb 23 – Mar 16
Broccoli, cabbageStart indoors · Jan 26 – Feb 9
Broccoli, cabbageTransplant · Mar 16 – Mar 30
Onion setsPlant outdoors · Mar 9 – Mar 23
PotatoesPlant outdoors · Mar 16 – Mar 30
LettuceSow outdoors · Mar 9 – Mar 23
Carrots, beetsSow outdoors · Mar 16 – Mar 30
TomatoesStart indoors · Feb 9 – Feb 23
TomatoesTransplant · Apr 13 – Apr 27
Peppers, eggplantStart indoors · Jan 26 – Feb 9
Peppers, eggplantTransplant · Apr 20 – May 4
BeansSow outdoors · Apr 13 – Apr 27
Sweet cornSow outdoors · Apr 13 – Apr 27
Cucumbers, squashSow outdoors · Apr 13 – Apr 27
Fall lettuce, spinachSow outdoors · Sep 15 – Sep 29
GarlicPlant cloves · Oct 27 – Dec 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 6) and first fall frost (Nov 10) 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 95979 came on Jan 21 — 13 days earlier than the 1991–2020 average (Feb 3).

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 Stonyford, CA

The soil mapped at the center of ZIP 95979 is Contra Costa — loam, well drained.

TextureLoama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Contra Costa-Millsholm complex, 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 95979; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Stonyford, CA

Summer high94 °Faverage high, July
Winter low32 °Faverage low, January
Hot days81days a year at 90 °F or more
Freezing nights60nights a year at 32 °F or less
Growing degree days4,039base 50 °F — the season’s usable heat
Longest day14 h 56 mindaylight on June 21
Shortest day9 h 24 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation21.8 inper year, rain and melted snow
Snowfall1 inper year

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 57 °F, low 32 °F 57°32° JanFebruary: average high 59 °F, low 35 °F 59°35° FebMarch: average high 63 °F, low 38 °F 63°38° MarApril: average high 69 °F, low 41 °F 69°41° AprMay: average high 78 °F, low 48 °F 78°48° MayJune: average high 88 °F, low 54 °F 88°54° JunJuly: average high 94 °F, low 60 °F 94°60° JulAugust: average high 93 °F, low 57 °F 93°57° AugSeptember: average high 89 °F, low 52 °F 89°52° SepOctober: average high 79 °F, low 45 °F 79°45° OctNovember: average high 65 °F, low 37 °F 65°37° NovDecember: average high 57 °F, low 32 °F 57°32° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 4.98 in precipitation, 0.7 in snowfall 5.0❄1 JanFebruary: 4.49 in precipitation, 0.7 in snowfall 4.5❄1 FebMarch: 2.84 in precipitation 2.8 MarApril: 1.18 in precipitation 1.2 AprMay: 0.93 in precipitation 0.9 MayJune: 0.33 in precipitation 0.3 JunJuly: 0.02 in precipitation 0.0 JulAugust: 0.05 in precipitation 0.1 AugSeptember: 0.15 in precipitation 0.1 SepOctober: 0.87 in precipitation 0.9 OctNovember: 2.13 in precipitation 2.1 NovDecember: 3.79 in precipitation 3.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: East Park Rsvr, CA (5 mi away); precipitation: East Park Rsvr, CA (5 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.

959559b
Maxwell, CA · 15 mi
959889b
Willows, CA · 17 mi
954239a
Clearlake Oaks, CA · 17 mi
959879b
Williams, CA · 18 mi
959399a
Elk Creek, CA · 20 mi
954439b
Glenhaven, CA · 22 mi
959709b
Princeton, CA · 24 mi
959329b
Colusa, CA · 25 mi

California planting zones →

Questions about 95979

What planting zone is ZIP code 95979?

ZIP code 95979 (Stonyford, CA) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Stonyford, CA?

The median last spring frost (32 °F) near 95979 is April 6; after April 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, East Park Rsvr station.

When is the first frost in Stonyford, CA?

The median first fall frost near 95979 is November 10, giving a median frost-free growing season of 219 days.

When should I plant tomatoes in 95979?

Start tomato seeds indoors around Feb 9 – Feb 23 and set transplants outside around Apr 13 – Apr 27, one to three weeks after the median last frost.

How much rain and snow does 95979 get?

About 21.8 inches of precipitation a year and 1 inches of snowfall (NOAA 1991–2020 normals, East Park Rsvr station).

How hot do summers get in Stonyford, CA?

The average high peaks at 94 °F in July, with about 81 days a year at 90 °F or more.

What kind of soil does 95979 have?

The USDA soil survey maps Contra Costa at the center of ZIP 95979: loam, well drained, pH about 6.5 (neutral).

Did spring come early in Stonyford, CA in 2026?

Spring leaf-out near 95979 came on Jan 21 in 2026, 13 days earlier than the 1991–2020 average (Feb 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Stonyford, CA?

Intermediate onions: the longest day near 95979 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 95979 change?

Yes. The 2012 USDA map put 95979 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.