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

Planting zone for Twentynine Palms, CA

Twentynine Palms, CA is in USDA zone 9b across its 2 ZIP codes. The median last spring frost is January 24 and the first fall frost December 10.

Twentynine Palms on the zone map

Outlined: its 2 ZIP code areas · 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

ZIP codes2

Last frostJan 24

First frostDec 10

Growing season321 days

9b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Twentynine Palms, 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 Twentynine Palms, CA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJanuary 24median — 50% chance of a later frost

Safe for tender plantsFebruary 22only 10% chance of frost after

First fall frostDecember 10median — 10% chance by Nov 24

Growing season321 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 3 and returns around December 23.

From the NOAA station Twentynine Palms, CA, elevation 1,975 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 Twentynine Palms

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Dec 13 – Dec 27

SpinachSow outdoors · Dec 13 – Jan 3

Broccoli, cabbageStart indoors · Nov 15 – Nov 29

Broccoli, cabbageTransplant · Jan 3 – Jan 17

Onion setsPlant outdoors · Dec 27 – Jan 10

PotatoesPlant outdoors · Jan 3 – Jan 17

LettuceSow outdoors · Dec 27 – Jan 10

Carrots, beetsSow outdoors · Jan 3 – Jan 17

TomatoesStart indoors · Nov 29 – Dec 13

TomatoesTransplant · Jan 31 – Feb 14

Peppers, eggplantStart indoors · Nov 15 – Nov 29

Peppers, eggplantTransplant · Feb 7 – Feb 21

BeansSow outdoors · Jan 31 – Feb 14

Sweet cornSow outdoors · Jan 31 – Feb 14

Cucumbers, squashSow outdoors · Jan 31 – Feb 14

Fall lettuce, spinachSow outdoors · Oct 15 – Oct 29

GarlicPlant cloves · Nov 26 – Dec 31

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 24) and first fall frost (Dec 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 92278 came on Jan 21 — 7 days earlier than the 1991–2020 average (Jan 28).

average
Jan 282026
Jan 21

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 Twentynine Palms, CA

The soil mapped at the center of ZIP 92278 is Cajon — coarse sand, somewhat excessively drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureCoarse sanddrains and warms fast; dries out and needs more feeding

pH8.8alkaline; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter0.05%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Cajon complex, 2 to 8 percent slpoes.

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 92278; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Twentynine Palms, CA

Summer high104 °Faverage high, July

Winter low40 °Faverage low, December

Hot days154days a year at 90 °F or more

Freezing nights17nights a year at 32 °F or less

Growing degree days7,576base 50 °F — the season’s usable heat

Longest day14 h 26 mindaylight on June 21

Shortest day9 h 52 mindaylight on December 21

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

Precipitation4.8 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: Twentynine Palms, CA (7 mi away); precipitation: Twentynine Palms 0.3 Nne, CA (6 mi away). Daylight is calculated from latitude.

ZIP codes in Twentynine Palms

California planting zones →

Questions about Twentynine Palms

What planting zone is Twentynine Palms, CA?

Twentynine Palms, CA is in USDA hardiness zone 9b on the 2023 map (9b: 25 to 30 °F).

When is the last frost in Twentynine Palms, CA?

The median last spring frost is January 24 and the median first fall frost is December 10 (NOAA 1991–2020 normals, Twentynine Palms station).

When can I plant a garden in Twentynine Palms, CA?

Cool-season crops like peas and spinach go in around Dec 13 – Jan 3; tomatoes, peppers, beans and squash after about Jan 31, once frost risk has passed.

What kind of onions grow in Twentynine Palms, CA?

Intermediate onions: the longest day is 14 h 26 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Twentynine Palms, CA get?

About 4.8 inches of precipitation a year (NOAA 1991–2020 normals).