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

Planting zone for 93240 — Lake Isabella, CA

ZIP code 93240 (Lake Isabella, Kern County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is April 5 and the first fall frost November 3.

Where ZIP 93240 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 5

First frostNov 3

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 Lake Isabella, 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 Lake Isabella, CA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 5median — 50% chance of a later frost

Safe for tender plantsApril 21only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 18

Growing season212 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 6 and returns around November 17.

From the NOAA station S Lake Fs, CA — 6 miles away, elevation 2,654 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 93240

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 22 – Mar 8

SpinachSow outdoors · Feb 22 – Mar 15

Broccoli, cabbageStart indoors · Jan 25 – Feb 8

Broccoli, cabbageTransplant · Mar 15 – Mar 29

Onion setsPlant outdoors · Mar 8 – Mar 22

PotatoesPlant outdoors · Mar 15 – Mar 29

LettuceSow outdoors · Mar 8 – Mar 22

Carrots, beetsSow outdoors · Mar 15 – Mar 29

TomatoesStart indoors · Feb 8 – Feb 22

TomatoesTransplant · Apr 12 – Apr 26

Peppers, eggplantStart indoors · Jan 25 – Feb 8

Peppers, eggplantTransplant · Apr 19 – May 3

BeansSow outdoors · Apr 12 – Apr 26

Sweet cornSow outdoors · Apr 12 – Apr 26

Cucumbers, squashSow outdoors · Apr 12 – Apr 26

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 5) and first fall frost (Nov 3) 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 93240 came on Jan 31 — 4 days earlier than the 1991–2020 average (Feb 4).

average
Feb 42026
Jan 31

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 Lake Isabella, CA

The soil mapped at the center of ZIP 93240 is Kernville — gravelly loamy coarse sand, somewhat excessively drained.

TextureGravelly loamy coarse sanddrains and warms fast; dries out and needs more feeding

pH6.7neutral; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Kernville-Faycreek-Rock outcrop complex, 30 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 93240; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lake Isabella, CA

Summer high98 °Faverage high, July

Winter low30 °Faverage low, January

Hot days114days a year at 90 °F or more

Freezing nights80nights a year at 32 °F or less

Growing degree days4,736base 50 °F — the season’s usable heat

Longest day14 h 34 mindaylight on June 21

Shortest day9 h 45 mindaylight on December 21

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

Precipitation11.8 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: S Lake Fs, CA (6 mi away); precipitation: Kern River Ph 3, CA (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Wofford Heights, CA · 9 mi

935188b

Caliente, CA · 16 mi

932388b

Kernville, CA · 16 mi

932268b

Glennville, CA · 18 mi

California planting zones →

Questions about 93240

What planting zone is ZIP code 93240?

ZIP code 93240 (Lake Isabella, 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 Lake Isabella, CA?

The median last spring frost (32 °F) near 93240 is April 5; after April 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, S Lake Fs station.

When is the first frost in Lake Isabella, CA?

The median first fall frost near 93240 is November 3, giving a median frost-free growing season of 212 days.

When should I plant tomatoes in 93240?

Start tomato seeds indoors around Feb 8 – Feb 22 and set transplants outside around Apr 12 – Apr 26, one to three weeks after the median last frost.

How much rain and snow does 93240 get?

About 11.8 inches of precipitation a year (NOAA 1991–2020 normals, Kern River Ph 3 station).

How hot do summers get in Lake Isabella, CA?

The average high peaks at 98 °F in July, with about 114 days a year at 90 °F or more.

What kind of soil does 93240 have?

The USDA soil survey maps Kernville at the center of ZIP 93240: gravelly loamy coarse sand, somewhat excessively drained, pH about 6.7 (neutral).

Did spring come early in Lake Isabella, CA in 2026?

Spring leaf-out near 93240 came on Jan 31 in 2026, 4 days earlier than the 1991–2020 average (Feb 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lake Isabella, CA?

Intermediate onions: the longest day near 93240 is 14 h 34 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 93240 change?

Yes. The 2012 USDA map put 93240 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.