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

Planting zone for 92347 — Hinkley, CA

ZIP code 92347 (Hinkley, San Bernardino County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is February 22 and the first fall frost November 23.

Where ZIP 92347 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 frostFeb 22
First frostNov 23
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 Hinkley, 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 Hinkley, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 22median — 50% chance of a later frost
Safe for tender plantsMarch 24only 10% chance of frost after
First fall frostNovember 23median — 10% chance by Nov 9
Growing season271 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 30 and returns around December 6.

From the NOAA station Barstow, CA — 14 miles away, elevation 2,221 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 92347

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 11 – Jan 25
SpinachSow outdoors · Jan 11 – Feb 1
Broccoli, cabbageStart indoors · Dec 14 – Dec 28
Broccoli, cabbageTransplant · Feb 1 – Feb 15
Onion setsPlant outdoors · Jan 25 – Feb 8
PotatoesPlant outdoors · Feb 1 – Feb 15
LettuceSow outdoors · Jan 25 – Feb 8
Carrots, beetsSow outdoors · Feb 1 – Feb 15
TomatoesStart indoors · Dec 28 – Jan 11
TomatoesTransplant · Mar 1 – Mar 15
Peppers, eggplantStart indoors · Dec 14 – Dec 28
Peppers, eggplantTransplant · Mar 8 – Mar 22
BeansSow outdoors · Mar 1 – Mar 15
Sweet cornSow outdoors · Mar 1 – Mar 15
Cucumbers, squashSow outdoors · Mar 1 – Mar 15
Fall lettuce, spinachSow outdoors · Sep 28 – Oct 12
GarlicPlant cloves · Nov 9 – Dec 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 22) and first fall frost (Nov 23) 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 92347 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 Hinkley, CA

The soil mapped at the center of ZIP 92347 is Norob — loamy sand, moderately well drained.

TextureLoamy sanddrains and warms fast; dries out and needs more feeding
pH7.5slightly alkaline; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter0.25%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: NOROB-HALLORAN COMPLEX, 0 TO 5 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 92347; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hinkley, CA

Summer high102 °Faverage high, July
Winter low35 °Faverage low, January
Hot days133days a year at 90 °F or more
Freezing nights32nights a year at 32 °F or less
Growing degree days6,141base 50 °F — the season’s usable heat
Longest day14 h 30 mindaylight on June 21
Shortest day9 h 48 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation5 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 59 °F, low 35 °F 59°35° JanFebruary: average high 63 °F, low 39 °F 63°39° FebMarch: average high 70 °F, low 44 °F 70°44° MarApril: average high 77 °F, low 49 °F 77°49° AprMay: average high 86 °F, low 57 °F 86°57° MayJune: average high 96 °F, low 65 °F 96°65° JunJuly: average high 102 °F, low 72 °F 102°72° JulAugust: average high 101 °F, low 70 °F 101°70° AugSeptember: average high 93 °F, low 63 °F 93°63° SepOctober: average high 81 °F, low 53 °F 81°53° OctNovember: average high 68 °F, low 42 °F 68°42° NovDecember: average high 57 °F, low 35 °F 57°35° Dec

Precipitation by month inches

0″1″January: 0.76 in precipitation 0.8 JanFebruary: 0.98 in precipitation 1.0 FebMarch: 0.59 in precipitation 0.6 MarApril: 0.30 in precipitation 0.3 AprMay: 0.06 in precipitation 0.1 MayJune: 0.04 in precipitation 0.0 JunJuly: 0.26 in precipitation 0.3 JulAugust: 0.17 in precipitation 0.2 AugSeptember: 0.25 in precipitation 0.3 SepOctober: 0.35 in precipitation 0.3 OctNovember: 0.40 in precipitation 0.4 NovDecember: 0.80 in precipitation, 0.3 in snowfall 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Barstow, CA (14 mi away); precipitation: Barstow, CA (14 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.

923129a
Barstow, CA · 14 mi
923428b
Helendale, CA · 14 mi
923119a
Barstow, CA · 15 mi
923688b
Oro Grande, CA · 20 mi
935168b
Boron, CA · 22 mi
935968b
Boron, CA · 22 mi
923018b
Adelanto, CA · 26 mi
923078b
Apple Valley, CA · 27 mi

California planting zones →

Questions about 92347

What planting zone is ZIP code 92347?

ZIP code 92347 (Hinkley, 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 Hinkley, CA?

The median last spring frost (32 °F) near 92347 is February 22; after March 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Barstow station.

When is the first frost in Hinkley, CA?

The median first fall frost near 92347 is November 23, giving a median frost-free growing season of 271 days.

When should I plant tomatoes in 92347?

Start tomato seeds indoors around Dec 28 – Jan 11 and set transplants outside around Mar 1 – Mar 15, one to three weeks after the median last frost.

How much rain and snow does 92347 get?

About 5 inches of precipitation a year (NOAA 1991–2020 normals, Barstow station).

How hot do summers get in Hinkley, CA?

The average high peaks at 102 °F in July, with about 133 days a year at 90 °F or more.

What kind of soil does 92347 have?

The USDA soil survey maps Norob at the center of ZIP 92347: loamy sand, moderately well drained, pH about 7.5 (slightly alkaline).

Did spring come early in Hinkley, CA in 2026?

Spring leaf-out near 92347 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 Hinkley, CA?

Intermediate onions: the longest day near 92347 is 14 h 30 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 92347 change?

Yes. The 2012 USDA map put 92347 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.