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

Planting zone for Sierra Madre, CA

Sierra Madre, CA is in USDA zone 10a across its 2 ZIP codes. The median last spring frost is April 28 and the first fall frost November 15.

Sierra Madre on the zone map

Outlined: its 1 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.

Zone10a30 to 35 °F
ZIP codes2
Last frostApr 28
First frostNov 15
Growing season199 days

10a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Sierra Madre, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 28median — 50% chance of a later frost
Safe for tender plantsMay 27only 10% chance of frost after
First fall frostNovember 15median — 10% chance by Oct 18
Growing season199 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 8 and returns around December 4.

From the NOAA station Mt Wilson Cbs, CA, elevation 5,709 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 Sierra Madre

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 17 – Mar 31
SpinachSow outdoors · Mar 17 – Apr 7
Broccoli, cabbageStart indoors · Feb 17 – Mar 3
Broccoli, cabbageTransplant · Apr 7 – Apr 21
Onion setsPlant outdoors · Mar 31 – Apr 14
PotatoesPlant outdoors · Apr 7 – Apr 21
LettuceSow outdoors · Mar 31 – Apr 14
Carrots, beetsSow outdoors · Apr 7 – Apr 21
TomatoesStart indoors · Mar 3 – Mar 17
TomatoesTransplant · May 5 – May 19
Peppers, eggplantStart indoors · Feb 17 – Mar 3
Peppers, eggplantTransplant · May 12 – May 26
BeansSow outdoors · May 5 – May 19
Sweet cornSow outdoors · May 5 – May 19
Cucumbers, squashSow outdoors · May 5 – May 19
Fall lettuce, spinachSow outdoors · Sep 20 – Oct 4
GarlicPlant cloves · Nov 1 – Dec 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 28) and first fall frost (Nov 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 91024 came on Jan 17 — 4 days earlier than the 1991–2020 average (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 Sierra Madre, CA

The soil mapped at the center of ZIP 91024 is Trigo family — loam, somewhat excessively drained.

TextureLoama good balance for most vegetables
pH6.7neutral; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter1%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Trigo family, granitic substratum, 60 to 90 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 91024; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sierra Madre, CA

Summer high85 °Faverage high, July
Winter low37 °Faverage low, February
Hot days16days a year at 90 °F or more
Freezing nights50nights a year at 32 °F or less
Growing degree days3,992base 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
Precipitation19.4 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 56 °F, low 38 °F 56°38° JanFebruary: average high 55 °F, low 37 °F 55°37° FebMarch: average high 59 °F, low 39 °F 59°39° MarApril: average high 63 °F, low 42 °F 63°42° AprMay: average high 70 °F, low 48 °F 70°48° MayJune: average high 79 °F, low 58 °F 79°58° JunJuly: average high 85 °F, low 64 °F 85°64° JulAugust: average high 85 °F, low 64 °F 85°64° AugSeptember: average high 81 °F, low 59 °F 81°59° SepOctober: average high 72 °F, low 51 °F 72°51° OctNovember: average high 63 °F, low 43 °F 63°43° NovDecember: average high 55 °F, low 37 °F 55°37° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.24 in precipitation 4.2 JanFebruary: 5.40 in precipitation 5.4 FebMarch: 2.93 in precipitation 2.9 MarApril: 1.05 in precipitation 1.1 AprMay: 0.59 in precipitation 0.6 MayJune: 0.18 in precipitation 0.2 JunJuly: 0.06 in precipitation 0.1 JulAugust: 0.01 in precipitation 0.0 AugSeptember: 0.18 in precipitation 0.2 SepOctober: 0.81 in precipitation 0.8 OctNovember: 1.09 in precipitation 1.1 NovDecember: 2.82 in precipitation 2.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mt Wilson Cbs, CA (4 mi away); precipitation: Pasadena 1.8 E, CA (4 mi away). Daylight is calculated from latitude.

ZIP codes in Sierra Madre

9102410a
30 to 35 °F
9102510a
30 to 35 °F

California planting zones →

Questions about Sierra Madre

What planting zone is Sierra Madre, CA?

Sierra Madre, CA is in USDA hardiness zone 10a on the 2023 map (10a: 30 to 35 °F).

When is the last frost in Sierra Madre, CA?

The median last spring frost is April 28 and the median first fall frost is November 15 (NOAA 1991–2020 normals, Mt Wilson Cbs station).

When can I plant a garden in Sierra Madre, CA?

Cool-season crops like peas and spinach go in around Mar 17 – Apr 7; tomatoes, peppers, beans and squash after about May 5, once frost risk has passed.

What kind of onions grow in Sierra Madre, 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 Sierra Madre, CA get?

About 19.4 inches of precipitation a year (NOAA 1991–2020 normals).