Los Altos Hills, 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.
These conditions suit okra, meyer lemon, california poppy, and artichoke — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Los Altos Hills, 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 Los Altos Hills 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 Los Altos Hills — soil, climate, flood, and parcel records. How we handle your address.
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Los Altos Hills — the short answer
Los Altos Hills, California: USDA zone 10a, about 331 days between hard freezes, across 6K acres of town.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 17
- Santa Clara County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 14
- Santa Clara County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~331
- Santa Clara County normal — NOAA 1991–2020, nearest to this town
- Town area
- 6K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Santa Clara County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Los Altos Hills's average, not your lot's — a low corner or a tree line moves it. Against Los Altos Hills's 331-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Los Altos Hills
Each reading below is measured for Los Altos Hills itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsLos Altos Hills runs about 331 days between hard freezes (read from Santa Clara County, the closest normal to Los Altos Hills) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredLos Altos Hills 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 Los Altos Hills is in
Los Altos Hills sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Los Altos Hills's own centroid rather than borrowed from Santa Clara County.
What Grows in Los Altos Hills
Every plant below cleared Los Altos Hills's own zone 10a and its 331-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Los Altos Hills?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 14 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
Documented around Los Altos Hills
Spotted lanternfly documented 27 miles from Los Altos Hills, first recorded 2023. What to watch for.
What's on the federal record near Los Altos Hills
Closest first, within ~10 miles of Los Altos Hills. Listing isn't leaking, and distance isn't exposure.
- VAHE TASHJIANBrownfields · 1700 ft
- SWEET CANYON JOINERYBrownfields · 2600 ft
- M. B. TAAFFE CO INCBrownfields · 0.5 mi
- CYNTHIA WAINBrownfields · 0.7 mi
- Foothill CollegeUnderground Storage Tanks · 0.8 mi
- SETON PROVINCIALATE / Daughters Of CharityUnderground Storage Tanks · 0.8 mi
- SETON PROVINCIALATEBrownfields · 0.8 mi
- CA WATER SERVICE CO LAS O KEEFE TANKSBrownfields · 0.8 mi
- PURISSIMA HILLS WATER DISTRICTPFAS · 0.9 mi
- TOWN OF LOS ALTOS HILLS CORPORATION YARDBrownfields · 0.9 mi
- BERNICE JEWORSKIBrownfields · 0.9 mi
- BARBARA ETISBrownfields · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Los Altos Hills'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 Los Altos Hills.
Sources Checked
within ~10 miles of Los Altos Hills
Severity Distribution
within ~10 miles of Los Altos Hills
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Los Altos Hills, Brownfields runs higher than the national average — 4,804 sites within ~10 miles of Los Altos Hills. That's not a problem with your land — it's information about 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 Los Altos Hills
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 Los Altos Hills average
Your land is one point inside Los Altos Hills
Everything above resolves to Los Altos Hills as a whole — one PHZM band, read across 6K acres, with hard-freeze dates borrowed from Santa Clara County’s record because no 30-year normal resolves at this town’s own centroid. 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 town 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 Los Altos Hills Average
Los Altos Hills Average
- ●USDA Zones 10a, averaged across Los Altos Hills
- ●One soil character for all of Los Altos Hills
- ●Frost dates read at Los Altos Hills's scale: Jan 17 to Dec 14
YOUR Parcel
- ✓Your exact zone, not Los Altos Hills's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Los Altos Hills
Pull a site-specific report for your exact address in Los Altos Hills, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Los Altos Hills averages can't show:
We read public map data around Los Altos Hills — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Los Altos Hills average
How we know this about Los Altos Hills
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Santa Clara County’s record, because none resolves here; 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 town grain anywhere on this page — there is no town-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 Los Altos Hills
When does frost risk typically end in Los Altos Hills?
The last hard freeze (28°F) in Los Altos Hills typically lands around Jan 17, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Feb 7.
When is the first frost in Los Altos Hills?
The first hard freeze (28°F) in Los Altos Hills typically arrives around Dec 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 30, so the watching starts about Nov 14 — about 331 days after the spring freeze cleared.
How long is the growing season in Los Altos Hills?
Measured between 28°F hard freezes, Los Altos Hills sees about 331 frost-free days — roughly Jan 17 through Dec 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 7 to Nov 30, about 296 days.
Is the soil safe to grow vegetables in Los Altos Hills?
The federal record around Los Altos Hills runs heavier than most — 5,427 documented sites, mostly Brownfields entries (4,804), the nearest Brownfields record about 0.3 miles 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.
How do I protect my plants from frost in Los Altos Hills?
From about Nov 14 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 14 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Los Altos Hills's scale — its 10a band and its 331-day season. Your yard writes its own version of Los Altos Hills'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 Los Altos Hills’s own scale
6 of the readings below were taken at Los Altos Hills's own scale — the 5,803 acres it covers and 5,427 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Los Altos Hills's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 5,427 documented contamination sites on the federal record near Los Altos Hills, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Los Altos Hills's boundary and the 5,803 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 10a and a ~331-day seasonGrowable Ground crop-matching engine
- The ecoregion at Los Altos Hills's own centroid, the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Los Altos Hillslydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Los Altos Hills has no normal of its own, so its county's is the closest measured readfrom Santa Clara County
- Soil character — no town-scale survey exists, so Los Altos Hills's 5,803 acres read through its county's SSURGO summaryfrom Santa Clara County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Santa Clara 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 Santa Clara County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Los Altos Hills's 5,803 acreswhy one lot differs from the next →
- Which side of Los Altos Hills you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 5,803 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.3 miles 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 Los Altos Hills-wide figureread your own land →
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