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

Planting zone for 95418 — Calpella, CA

ZIP code 95418 (Calpella, Mendocino County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 19 and the first fall frost November 20.

Where ZIP 95418 is

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 frostMar 19
First frostNov 20
2012 zone9a

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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Calpella, 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 Calpella, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 19median — 50% chance of a later frost
Safe for tender plantsApril 15only 10% chance of frost after
First fall frostNovember 20median — 10% chance by Nov 2
Growing season245 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 6 and returns around December 5.

From the NOAA station Ukiah, CA — 5 miles away, elevation 637 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 95418

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 5 – Feb 19
SpinachSow outdoors · Feb 5 – Feb 26
Broccoli, cabbageStart indoors · Jan 8 – Jan 22
Broccoli, cabbageTransplant · Feb 26 – Mar 12
Onion setsPlant outdoors · Feb 19 – Mar 5
PotatoesPlant outdoors · Feb 26 – Mar 12
LettuceSow outdoors · Feb 19 – Mar 5
Carrots, beetsSow outdoors · Feb 26 – Mar 12
TomatoesStart indoors · Jan 22 – Feb 5
TomatoesTransplant · Mar 26 – Apr 9
Peppers, eggplantStart indoors · Jan 8 – Jan 22
Peppers, eggplantTransplant · Apr 2 – Apr 16
BeansSow outdoors · Mar 26 – Apr 9
Sweet cornSow outdoors · Mar 26 – Apr 9
Cucumbers, squashSow outdoors · Mar 26 – Apr 9
Fall lettuce, spinachSow outdoors · Sep 25 – Oct 9
GarlicPlant cloves · Nov 6 – Dec 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 19) and first fall frost (Nov 20) 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 95418 came on Jan 30 — about the same time as 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 Calpella, CA

The soil mapped at the center of ZIP 95418 is Xerochrepts — gravelly loam, well drained.

TextureGravelly loama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Xerochrepts-Haploxeralfs-Argixerolls complex, 9 to 30 percent slopes, high ffd.

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 95418; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Calpella, CA

Summer high91 °Faverage high, July
Winter low36 °Faverage low, December
Hot days61days a year at 90 °F or more
Freezing nights34nights a year at 32 °F or less
Growing degree days3,702base 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
Precipitation38.4 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 57 °F, low 37 °F 57°37° JanFebruary: average high 60 °F, low 38 °F 60°38° FebMarch: average high 65 °F, low 40 °F 65°40° MarApril: average high 70 °F, low 42 °F 70°42° AprMay: average high 76 °F, low 47 °F 76°47° MayJune: average high 83 °F, low 52 °F 83°52° JunJuly: average high 91 °F, low 56 °F 91°56° JulAugust: average high 91 °F, low 54 °F 91°54° AugSeptember: average high 87 °F, low 51 °F 87°51° SepOctober: average high 77 °F, low 46 °F 77°46° OctNovember: average high 63 °F, low 40 °F 63°40° NovDecember: average high 56 °F, low 36 °F 56°36° Dec

Precipitation by month inches

0″2″4″6″8″January: 6.91 in precipitation 6.9 JanFebruary: 6.53 in precipitation 6.5 FebMarch: 5.18 in precipitation 5.2 MarApril: 2.70 in precipitation 2.7 AprMay: 1.46 in precipitation 1.5 MayJune: 0.38 in precipitation 0.4 JunJuly: 0.03 in precipitation 0.0 JulAugust: 0.09 in precipitation 0.1 AugSeptember: 0.17 in precipitation 0.2 SepOctober: 2.04 in precipitation 2.0 OctNovember: 4.40 in precipitation 4.4 NovDecember: 8.54 in precipitation 8.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ukiah, CA (5 mi away); precipitation: Redwood Valley 1.5 Ene, CA (4 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.

954709a
Redwood Valley, CA · 6 mi
954829a
Ukiah, CA · 6 mi
954819a
Talmage, CA · 7 mi
954938b
Witter Springs, CA · 12 mi
954699a
Potter Valley, CA · 14 mi
954859a
Upper Lake, CA · 16 mi
954159b
Boonville, CA · 16 mi
954538b
Lakeport, CA · 19 mi

California planting zones →

Questions about 95418

What planting zone is ZIP code 95418?

ZIP code 95418 (Calpella, 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 Calpella, CA?

The median last spring frost (32 °F) near 95418 is March 19; after April 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ukiah station.

When is the first frost in Calpella, CA?

The median first fall frost near 95418 is November 20, giving a median frost-free growing season of 245 days.

When should I plant tomatoes in 95418?

Start tomato seeds indoors around Jan 22 – Feb 5 and set transplants outside around Mar 26 – Apr 9, one to three weeks after the median last frost.

How much rain and snow does 95418 get?

About 38.4 inches of precipitation a year (NOAA 1991–2020 normals, Redwood Valley 1.5 Ene station).

How hot do summers get in Calpella, CA?

The average high peaks at 91 °F in July, with about 61 days a year at 90 °F or more.

What kind of soil does 95418 have?

The USDA soil survey maps Xerochrepts at the center of ZIP 95418: gravelly loam, well drained, pH about 7.0 (neutral).

Did spring come early in Calpella, CA in 2026?

Spring leaf-out near 95418 came on Jan 30 in 2026, about the same as the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Calpella, CA?

Intermediate onions: the longest day near 95418 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.