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

Planting zone for 90409 — Santa Monica, CA

ZIP code 90409 (Santa Monica, Los Angeles County) is in USDA zone 11a: the coldest winter night averages 40 to 45 °F. The median last spring frost is January 24 and the first fall frost December 15.

Where ZIP 90409 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.

Zone11a40 to 45 °F
Coldest night4.4 to 7.2 °C
Last frostJan 24
First frostDec 15
2012 zone10b

Was 10b 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 11a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Santa Monica, 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 Santa Monica, 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 plantsMarch 5only 10% chance of frost after
First fall frostDecember 15median — 10% chance by Nov 27
Growing season329 daysfrost-free, median

A hard freeze (28 °F) usually ends around December 31 and returns around December 26.

From the NOAA station Woodland Hills Pierce College, CA — 12 miles away, elevation 791 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 90409

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 20 – Nov 3
GarlicPlant cloves · Dec 1 – Jan 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 24) and first fall frost (Dec 15) 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 90409 came on Jan 17 — 3 days earlier than the 1991–2020 average (Jan 20).

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 Santa Monica, CA

The soil mapped at the center of ZIP 90409 is Pierview — loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureLoama good balance for most vegetables
pH7.5slightly alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Urban land-Pierview 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 90409; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Santa Monica, CA

Summer high70 °Faverage high, August
Winter low50 °Faverage low, January
Hot days1days a year at 90 °F or more
Freezing nights0nights a year at 32 °F or less
Growing degree days3,847base 50 °F — the season’s usable heat
Longest day14 h 25 mindaylight on June 21
Shortest day9 h 53 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation12.2 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°January: average high 62 °F, low 50 °F 62°50° JanFebruary: average high 62 °F, low 50 °F 62°50° FebMarch: average high 62 °F, low 52 °F 62°52° MarApril: average high 63 °F, low 53 °F 63°53° AprMay: average high 63 °F, low 56 °F 63°56° MayJune: average high 66 °F, low 59 °F 66°59° JunJuly: average high 69 °F, low 62 °F 69°62° JulAugust: average high 70 °F, low 62 °F 70°62° AugSeptember: average high 70 °F, low 61 °F 70°61° SepOctober: average high 68 °F, low 59 °F 68°59° OctNovember: average high 67 °F, low 54 °F 67°54° NovDecember: average high 63 °F, low 50 °F 63°50° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.08 in precipitation 3.1 JanFebruary: 3.10 in precipitation 3.1 FebMarch: 1.74 in precipitation 1.7 MarApril: 0.57 in precipitation 0.6 AprMay: 0.23 in precipitation 0.2 MayJune: 0.05 in precipitation 0.1 JunJuly: 0.03 in precipitation 0.0 JulAugust: 0.01 in precipitation 0.0 AugSeptember: 0.03 in precipitation 0.0 SepOctober: 0.49 in precipitation 0.5 OctNovember: 0.81 in precipitation 0.8 NovDecember: 2.03 in precipitation 2.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Santa Monica Pier, CA (within 1 mile); precipitation: Santa Monica Pier, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 11a.

9040611a
Santa Monica, CA · <1 mi
9040711a
Santa Monica, CA · <1 mi
9040811a
Santa Monica, CA · <1 mi
9041011a
Santa Monica, CA · <1 mi
9041111a
Santa Monica, CA · <1 mi
9040111a
Santa Monica, CA · <1 mi
9040311a
Santa Monica, CA · <1 mi
9040411a
Santa Monica, CA · 1 mi

All 11 ZIP codes in Santa Monica → · California planting zones →

Questions about 90409

What planting zone is ZIP code 90409?

ZIP code 90409 (Santa Monica, CA) is in USDA hardiness zone 11a on the 2023 map: the coldest night of an average winter reaches 40 to 45 °F (4.4 to 7.2 °C).

When is the last frost in Santa Monica, CA?

The median last spring frost (32 °F) near 90409 is January 24; after March 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Woodland Hills Pierce College station.

When is the first frost in Santa Monica, CA?

The median first fall frost near 90409 is December 15, giving a median frost-free growing season of 329 days.

When should I plant tomatoes in 90409?

Start tomato seeds indoors around Nov 29 – Dec 13 and set transplants outside around Jan 31 – Feb 14, one to three weeks after the median last frost.

How much rain and snow does 90409 get?

About 12.2 inches of precipitation a year (NOAA 1991–2020 normals, Santa Monica Pier station).

How hot do summers get in Santa Monica, CA?

The average high peaks at 70 °F in August, with about 1 days a year at 90 °F or more.

What kind of soil does 90409 have?

The USDA soil survey maps Pierview at the center of ZIP 90409: loam, well drained, pH about 7.5 (slightly alkaline).

Did spring come early in Santa Monica, CA in 2026?

Spring leaf-out near 90409 came on Jan 17 in 2026, 3 days earlier than the 1991–2020 average (Jan 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Santa Monica, CA?

Intermediate onions: the longest day near 90409 is 14 h 25 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 90409 change?

Yes. The 2012 USDA map put 90409 in zone 10b; the 2023 map puts it in zone 11a. The newer map uses 1991–2020 data and more weather stations.