San Dimas, California, sits in USDA hardiness zone 10a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Crops well matched to these conditions include artichoke, meyer lemon, california poppy, and cabbage — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in San Dimas, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single San Dimas lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around San Dimas — soil, climate, flood, and parcel records. How we handle your address.
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San Dimas — the short answer
San Dimas, California: USDA zone 10a, no 28°F killing freeze on record — the season is year-round, across 10K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Killing freeze
- None on record
- NOAA RCC ACIS 1991–2020, this town’s own record
- City area
- 10K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. The year-round finding is measured — a 30-year record with no 28°F killing freeze in it — never inferred from missing dates.
Hardiness Zone Range
Zone 10a is San Dimas's average, not your lot's — a low corner or a tree line moves it. Against San Dimas's no killing freeze on record, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Dimas
Each reading below is measured for San Dimas itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Winter hardiness
MeasuredSan Dimas sits in USDA hardiness zone 10a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country San Dimas is in
San Dimas sits in the Southern California/Northern Baja Coast — EPA Level III, inside the wider Mediterranean California. That is read at San Dimas's own centroid rather than borrowed from Los Angeles County.
What Grows in San Dimas
Every plant below cleared San Dimas's own zone 10a. Each card opens that plant's California profile. How we score.
What's on the federal record near San Dimas
Closest first, within ~10 miles of San Dimas. Listing isn't leaking, and distance isn't exposure.
- Frontier California: San Dimas COUnderground Storage Tanks · 400 ft
- WALKER HOUSEBrownfields · 450 ft
- SAN DIMAS CHEVRONUnderground Storage Tanks · 500 ft
- CITY OF SAN DIMASBrownfields · 650 ft
- CHEVRON STATION NO 91099Brownfields · 650 ft
- CERTIFIED TIRE & SERVICE CENTER SAN DIMASBrownfields · 700 ft
- SATA LAWNMOWER SHOPBrownfields · 700 ft
- SAN DIMAS RED PHOSPHOROUSSuperfund · 750 ft
- EASTSHORE-REC VEHICLE PARKSuperfund · 750 ft
- SAN DIMAS CLEANER KYUNG WHANGBrownfields · 850 ft
- DELISA CELAYA DDSBrownfields · 950 ft
- DOLLAR TREE #02883Brownfields · 1200 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from San Dimas's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near San Dimas.
Sources Checked
within ~10 miles of San Dimas
Severity Distribution
within ~10 miles of San Dimas
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Dimas, Brownfields runs higher than the national average — 5,642 sites within ~10 miles of San Dimas. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in San Dimas
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the San Dimas average
Your land is one point inside San Dimas
Everything above resolves to San Dimas as a whole — one PHZM band and one 28°F frost record, read across 10K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the San Dimas Average
San Dimas Average
- ●USDA Zones 10a, averaged across San Dimas
- ●One soil character for all of San Dimas
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not San Dimas's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Dimas
Pull a site-specific report for your exact address in San Dimas, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Dimas averages can't show:
We read public map data around San Dimas — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Dimas average
How we know this about San Dimas
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals, with the labelled statewide window where none resolves; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about San Dimas
Is it too late to plant in San Dimas?
No — San Dimas has no 28°F killing freeze in the 30-year station record, so the growing season is year-round and there is no last-frost date to wait for. Planting is paced by rainfall, heat and daylength instead of by frost: start heat-lovers any month, and time cool-season crops (lettuce, brassicas, peas) for the cooler, wetter half of the year or for higher ground. Succession sowing every few weeks works all year, so the limit is what you can keep watered and harvested, not the calendar.
When does frost risk typically end in San Dimas?
It doesn't — San Dimas records no 28°F killing freeze at all across the 1991–2020 station record, so there is no spring frost date to plant after. Cold still matters with elevation: the higher you garden, the cooler the nights, and a few tropical crops sulk below about 60°F even where they never freeze.
How long is the growing season in San Dimas?
Year-round — the 1991–2020 station record for San Dimas contains no 28°F killing freeze, so there is no season to measure between freezes. What paces planting instead is heat, rainfall and daylength: the hottest, wettest stretch is the hard part for cool-season crops, not winter. Elevation is the one real exception — the higher you garden, the colder the nights get.
Is the soil safe to grow vegetables in San Dimas?
The federal record around San Dimas runs heavier than most — 6,249 documented sites, mostly Brownfields entries (5,642), the nearest Underground Storage Tanks record under a tenth of a mile out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Everything above is measured at San Dimas's scale — its 10a band and its no killing freeze on record. Your yard writes its own version of San Dimas's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at San Dimas’s own scale
6 of the readings below were taken at San Dimas's own scale — the 9,622 acres it covers and 6,249 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- San Dimas's own USDA hardiness band, zones 10aUSDA PHZM 2023
- No 28°F killing freeze in the 30-year station record covering San Dimas — a year-round growing seasonNOAA Regional Climate Centers ACIS, 1991-2020
- 6,249 documented contamination sites on the federal record near San Dimas, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- San Dimas's boundary and the 9,622 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear San Dimas's hardiness zoneGrowable Ground crop-matching engine
- The ecoregion at San Dimas's own centroid, the Southern California/Northern Baja CoastUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so San Dimas's 9,622 acres read through its county's SSURGO summaryfrom Los Angeles County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Los Angeles County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Los Angeles County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among San Dimas's 9,622 acreswhy one lot differs from the next →
- Which side of San Dimas you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 9,622 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any San Dimas-wide figureread your own land →