Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 95305 — Big Oak Flat, CA

ZIP code 95305 (Big Oak Flat, Tuolumne County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is April 22 and the first fall frost November 2.

Where ZIP 95305 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 frostApr 22

First frostNov 2

2012 zone8b

Was 8b on the 2012 map — a full zone warmer now. 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 Big Oak Flat, 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 Big Oak Flat, CA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 22median — 50% chance of a later frost

Safe for tender plantsMay 14only 10% chance of frost after

First fall frostNovember 2median — 10% chance by Oct 13

Growing season192 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 19.

From the NOAA station Groveland 2, CA — 7 miles away, elevation 2,799 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 95305

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 11 – Mar 25

SpinachSow outdoors · Mar 11 – Apr 1

Broccoli, cabbageStart indoors · Feb 11 – Feb 25

Broccoli, cabbageTransplant · Apr 1 – Apr 15

Onion setsPlant outdoors · Mar 25 – Apr 8

PotatoesPlant outdoors · Apr 1 – Apr 15

LettuceSow outdoors · Mar 25 – Apr 8

Carrots, beetsSow outdoors · Apr 1 – Apr 15

TomatoesStart indoors · Feb 25 – Mar 11

TomatoesTransplant · Apr 29 – May 13

Peppers, eggplantStart indoors · Feb 11 – Feb 25

Peppers, eggplantTransplant · May 6 – May 20

BeansSow outdoors · Apr 29 – May 13

Sweet cornSow outdoors · Apr 29 – May 13

Cucumbers, squashSow outdoors · Apr 29 – May 13

Fall lettuce, spinachSow outdoors · Sep 7 – Sep 21

GarlicPlant cloves · Oct 19 – Nov 23

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 22) and first fall frost (Nov 2) 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 95305 came on Jan 30 — 3 days earlier than the 1991–2020 average (Feb 2).

average
Feb 22026
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 Big Oak Flat, CA

The soil mapped at the center of ZIP 95305 is Loafercreek — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH5.5moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter75%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Loafercreek-Gopheridge complex, 30 to 60 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 95305; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Big Oak Flat, CA

Summer high91 °Faverage high, July

Winter low31 °Faverage low, January

Hot days59days a year at 90 °F or more

Freezing nights91nights a year at 32 °F or less

Growing degree days3,242base 50 °F — the season’s usable heat

Longest day14 h 47 mindaylight on June 21

Shortest day9 h 32 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation38.7 inper year, rain and melted snow

Snowfall4 inper year; 2 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Groveland 2, CA (7 mi away); precipitation: Groveland 2, CA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

953479b

Moccasin, CA · 3 mi

953099b

Chinese Camp, CA · 5 mi

953279b

Jamestown, CA · 7 mi

953299b

La Grange, CA · 10 mi

Soulsbyville, CA · 13 mi

California planting zones →

Questions about 95305

What planting zone is ZIP code 95305?

ZIP code 95305 (Big Oak Flat, 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 Big Oak Flat, CA?

The median last spring frost (32 °F) near 95305 is April 22; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Groveland 2 station.

When is the first frost in Big Oak Flat, CA?

The median first fall frost near 95305 is November 2, giving a median frost-free growing season of 192 days.

When should I plant tomatoes in 95305?

Start tomato seeds indoors around Feb 25 – Mar 11 and set transplants outside around Apr 29 – May 13, one to three weeks after the median last frost.

How much rain and snow does 95305 get?

About 38.7 inches of precipitation a year and 4 inches of snowfall (NOAA 1991–2020 normals, Groveland 2 station).

How hot do summers get in Big Oak Flat, CA?

The average high peaks at 91 °F in July, with about 59 days a year at 90 °F or more.

What kind of soil does 95305 have?

The USDA soil survey maps Loafercreek at the center of ZIP 95305: slightly decomposed plant material, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Big Oak Flat, CA in 2026?

Spring leaf-out near 95305 came on Jan 30 in 2026, 3 days earlier than the 1991–2020 average (Feb 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Big Oak Flat, CA?

Intermediate onions: the longest day near 95305 is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 95305 change?

Yes. The 2012 USDA map put 95305 in zone 8b; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.