Dillon Beach, 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.
Growers here do well with okra, meyer lemon, california poppy, and artichoke — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Dillon Beach, 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 Dillon Beach 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 Dillon Beach — soil, climate, flood, and parcel records. How we handle your address.
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Dillon Beach — the short answer
Dillon Beach, California: USDA zone 10a, about 336 days between hard freezes, across 2K acres of town.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 9
- Marin County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 11
- Marin County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~336
- Marin County normal — NOAA 1991–2020, nearest to this town
- Town area
- 2K 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 Marin County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Dillon Beach's average, not your lot's — a low corner or a tree line moves it. Against Dillon Beach's 336-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dillon Beach
Each reading below is measured for Dillon Beach itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsDillon Beach runs about 336 days between hard freezes (read from Marin County, the closest normal to Dillon Beach) — 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
MeasuredDillon Beach 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 Dillon Beach is in
Dillon Beach sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Dillon Beach's own centroid rather than borrowed from Marin County.
What Grows in Dillon Beach
Every plant below cleared Dillon Beach's own zone 10a and its 336-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Dillon Beach?
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 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 11 — 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.
What's on the federal record near Dillon Beach
Closest first, within ~10 miles of Dillon Beach. Listing isn't leaking, and distance isn't exposure.
- CALIFORNIA WATER SERVICE CO CSTPBrownfields · 0.5 mi
- LAWSON S LANDINGBrownfields · 0.6 mi
- 005N010W21Q001MNitrate · 0.9 mi
- COUNTY OF MARIN FIRE TOMALESBrownfields · 2.5 mi
- PACIFIC BELLBrownfields · 2.7 mi
- 005N010W25J001MNitrate · 2.7 mi
- SHORELINE UNIFIED SCH DISTBrownfields · 2.8 mi
- F/V AMERICAN CHALLENGERSuperfund · 3.3 mi
- 005N010W11Q001MNitrate · 3.3 mi
- 005N009W30F001MNitrate · 3.4 mi
- THORNTON DAIRYBrownfields · 4.4 mi
- BLAKES LANDING FARMS INCBrownfields · 4.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dillon Beach'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 Dillon Beach.
Total Sites
61
within ~10 miles of Dillon Beach
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Dillon Beach
Severity Distribution
within ~10 miles of Dillon Beach
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dillon Beach, two things run higher than the national average within ~10 miles of Dillon Beach — Brownfields (39 sites) and Mining (4 sites). 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.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Dillon Beach
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 Dillon Beach average
Your land is one point inside Dillon Beach
Everything above resolves to Dillon Beach as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Marin 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 Dillon Beach Average
Dillon Beach Average
- ●USDA Zones 10a, averaged across Dillon Beach
- ●One soil character for all of Dillon Beach
- ●Frost dates read at Dillon Beach's scale: Jan 9 to Dec 11
YOUR Parcel
- ✓Your exact zone, not Dillon Beach's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dillon Beach
Pull a site-specific report for your exact address in Dillon Beach, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dillon Beach averages can't show:
We read public map data around Dillon Beach — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dillon Beach average
How we know this about Dillon Beach
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 Marin 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 Dillon Beach
When does frost risk typically end in Dillon Beach?
The last hard freeze (28°F) in Dillon Beach typically lands around Jan 9, 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 Jan 30.
When is the first frost in Dillon Beach?
The first hard freeze (28°F) in Dillon Beach typically arrives around Dec 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 27, so the watching starts about Nov 11 — about 336 days after the spring freeze cleared.
How long is the growing season in Dillon Beach?
Measured between 28°F hard freezes, Dillon Beach sees about 336 frost-free days — roughly Jan 9 through Dec 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jan 30 to Nov 27, about 301 days.
Is the soil safe to grow vegetables in Dillon Beach?
The federal record around Dillon Beach is a meaningful one — 61 documented sites, mostly Brownfields entries (39), the nearest Brownfields record about 0.5 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Dillon Beach?
From about Nov 11 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dillon Beach's scale — its 10a band and its 336-day season. Your yard writes its own version of Dillon Beach'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 Dillon Beach’s own scale
5 of the readings below were taken at Dillon Beach's own scale — the 1,910 acres it covers and 61 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Dillon Beach's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 61 documented contamination sites on the federal record near Dillon Beach, the closest Brownfields record about 0.5 miles out from the town centreFederal environmental registers
- Dillon Beach's boundary and the 1,910 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 10a and a ~336-day seasonGrowable Ground crop-matching engine
- The ecoregion at Dillon Beach's own centroid, the Central California Foothills and Coastal MountainsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Dillon Beach has no normal of its own, so its county's is the closest measured readfrom Marin County
- Soil character — no town-scale survey exists, so Dillon Beach's 1,910 acres read through its county's SSURGO summaryfrom Marin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Marin 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 Marin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dillon Beach's 1,910 acreswhy one lot differs from the next →
- Which side of Dillon Beach you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,910 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.5 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 Dillon Beach-wide figureread your own land →
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