Somerton, Arizona, sits in USDA hardiness zone 10a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, palo verde, citrus, jalapeno, and date palm all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Somerton, 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 Somerton 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 Somerton — soil, climate, flood, and parcel records. How we handle your address.
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Somerton — the short answer
Somerton, Arizona: USDA zone 10a, about 316 days between hard freezes, across 5K acres of city.
- USDA zone
- 10a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 29
- Yuma County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 11
- Yuma County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~316
- Yuma County normal — NOAA 1991–2020, nearest to this town
- City area
- 5K 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 Yuma County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 10a is Somerton's average, not your lot's — a low corner or a tree line moves it. Against Somerton's 316-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Somerton
Each reading below is measured for Somerton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSomerton runs about 316 days between hard freezes (read from Yuma County, the closest normal to Somerton) — 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
MeasuredSomerton 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 Somerton is in
Somerton sits in the Sonoran Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Somerton's own centroid rather than borrowed from Yuma County.
What Grows in Somerton
Plants matched to Somerton's USDA zones 10a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Somerton?
For most of the year, no — what changes is which crops still fit the days remaining. 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 29 (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. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
Documented around Somerton
Survey cells within 31 miles of Somerton checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 149 miles off. What to watch for.
What's on the federal record near Somerton
Closest first, within ~10 miles of Somerton. Listing isn't leaking, and distance isn't exposure.
- SUPER GASUnderground Storage Tanks · 0.6 mi
- FAMILY DOLLAR #5494Brownfields · 0.6 mi
- WESTERN FARM SERVICE DESERT DIVISION - SOMERTONUnderground Storage Tanks · 0.6 mi
- CITY OF SOMERTON - PUBLIC WORKS YARDUnderground Storage Tanks · 0.8 mi
- SHAY OIL #7Underground Storage Tanks · 0.8 mi
- CIRCLE K #1939Underground Storage Tanks · 0.8 mi
- SOMERTON LANDFILLSuperfund · 0.9 mi
- SHAY OIL - SOMERTONUnderground Storage Tanks · 0.9 mi
- SOMERTON AUTO & TIRE CENTERUnderground Storage Tanks · 0.9 mi
- CIRCLE K #918Underground Storage Tanks · 1.0 mi
- SOMERTON SCHOOL DISTRICTUnderground Storage Tanks · 1.1 mi
- C-09-24 36CAA1Nitrate · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Somerton'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 Somerton.
Sources Checked
within ~10 miles of Somerton
Severity Distribution
within ~10 miles of Somerton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Somerton, Superfund runs higher than the national average — 9 sites within ~10 miles of Somerton. That's not a problem with your land — it's information about it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Somerton
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 Somerton average
Your land is one point inside Somerton
Everything above resolves to Somerton as a whole — one PHZM band, read across 5K acres, with hard-freeze dates borrowed from Yuma County’s record because no 30-year normal resolves at this city’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 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 Somerton Average
Somerton Average
- ●USDA Zones 10a, averaged across Somerton
- ●One soil character for all of Somerton
- ●Frost dates read at Somerton's scale: Jan 29 to Dec 11
YOUR Parcel
- ✓Your exact zone, not Somerton's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Somerton
Pull a site-specific report for your exact address in Somerton, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Somerton averages can't show:
We read public map data around Somerton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Somerton average
How we know this about Somerton
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 at Yuma 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 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 Somerton
When does frost risk typically end in Somerton?
The last hard freeze (28°F) in Somerton typically lands around Jan 29, 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 19.
When is the first frost in Somerton?
The first hard freeze (28°F) in Somerton 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 316 days after the spring freeze cleared.
How long is the growing season in Somerton?
Measured between 28°F hard freezes, Somerton sees about 316 frost-free days — roughly Jan 29 through Dec 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 19 to Nov 27, about 281 days.
Is the soil safe to grow vegetables in Somerton?
The federal record around Somerton is a meaningful one — 489 documented sites, mostly Underground Storage Tanks entries (253), the nearest Underground Storage Tanks record about 0.6 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 Somerton?
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 Somerton's scale — its 10a band and its 316-day season. Your yard writes its own version of Somerton'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 Somerton’s own scale
5 of the readings below were taken at Somerton's own scale — the 4,655 acres it covers and 489 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Somerton's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 489 documented contamination sites on the federal record near Somerton, the closest Underground Storage Tanks record about 0.6 miles out from the town centreFederal environmental registers
- Somerton's boundary and the 4,655 acres inside itUS Census TIGER/Line 2025
- The ecoregion at Somerton's own centroid, the Sonoran Basin and RangeUS EPA Level III Ecoregions
- Lanternfly survey cells around Somerton checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Somerton has no normal of its own, so its county's is the closest measured readfrom Yuma County
- Soil character — no town-scale survey exists, so Somerton's 4,655 acres read through its county's SSURGO summaryfrom Yuma County
- The candidate plant list — Arizona's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom Arizona
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Yuma County
- The growing challenges every Arizona grower plans around — written at state scale, so they stay on the state guidefrom Arizona
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Yuma County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Somerton's 4,655 acreswhy one lot differs from the next →
- Which side of Somerton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,655 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.6 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 Somerton-wide figureread your own land →