San Luis, Arizona, 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.
The conditions favor palo verde, citrus, jalapeno, and date palm, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in San Luis, 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 Luis 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 Luis — soil, climate, flood, and parcel records. How we handle your address.
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San Luis — the short answer
San Luis, Arizona: USDA zone 10a, about 316 days between hard freezes, across 22K 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
- 22K 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 San Luis's average, not your lot's — a low corner or a tree line moves it. Against San Luis's 316-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in San Luis
Each reading below is measured for San Luis itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSan Luis runs about 316 days between hard freezes (read from Yuma County, the closest normal to San Luis) — 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
MeasuredSan Luis 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 Luis is in
San Luis sits in the Sonoran Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at San Luis's own centroid rather than borrowed from Yuma County.
What Grows in San Luis
Plants matched to San Luis'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 San Luis?
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 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. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
Documented around San Luis
Survey cells within 31 miles of San Luis checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 150 miles off. What to watch for.
What's on the federal record near San Luis
Closest first, within ~10 miles of San Luis. Listing isn't leaking, and distance isn't exposure.
- C-11-24 23BCB1Nitrate · 2.2 mi
- C-11-24 11DDD1Nitrate · 2.3 mi
- SAN LUIS CITY OFPFAS · 2.3 mi
- ASPC YUMAPFAS · 2.3 mi
- SUPER CUnderground Storage Tanks · 2.4 mi
- VIRCO MANUFACTURINGUnderground Storage Tanks · 3.3 mi
- FRANKS SERVICE & TRUCKING LLCBrownfields · 3.3 mi
- USDOJ INS - SAN LUIS PORT OF ENTRYUnderground Storage Tanks · 3.4 mi
- TRIPLE BUnderground Storage Tanks · 3.5 mi
- C-11-25 12CAB1Nitrate · 3.5 mi
- SHAY OIL CO #15Underground Storage Tanks · 3.5 mi
- CHEVRON SELF SERVE 15Brownfields · 3.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from San Luis'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 Luis.
Total Sites
94
within ~10 miles of San Luis
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of San Luis
Severity Distribution
within ~10 miles of San Luis
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around San Luis, two things run higher than the national average within ~10 miles of San Luis — PFAS (3 sites) and Nitrate (52 sites). That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in San Luis
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 Luis average
Your land is one point inside San Luis
Everything above resolves to San Luis as a whole — one PHZM band, read across 22K 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 San Luis Average
San Luis Average
- ●USDA Zones 10a, averaged across San Luis
- ●One soil character for all of San Luis
- ●Frost dates read at San Luis's scale: Jan 29 to Dec 11
YOUR Parcel
- ✓Your exact zone, not San Luis's 10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in San Luis
Pull a site-specific report for your exact address in San Luis, Arizona — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that San Luis averages can't show:
We read public map data around San Luis — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the San Luis average
How we know this about San Luis
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 San Luis
When does frost risk typically end in San Luis?
The last hard freeze (28°F) in San Luis 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 San Luis?
The first hard freeze (28°F) in San Luis 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 San Luis?
Measured between 28°F hard freezes, San Luis 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 San Luis?
The federal record around San Luis is a meaningful one — 94 documented sites, mostly Nitrate entries (52), the nearest Nitrate record about 2.2 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 San Luis?
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 San Luis's scale — its 10a band and its 316-day season. Your yard writes its own version of San Luis'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 Luis’s own scale
5 of the readings below were taken at San Luis's own scale — the 21,646 acres it covers and 94 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- San Luis's own USDA hardiness band, zones 10aUSDA PHZM 2023
- 94 documented contamination sites on the federal record near San Luis, the closest Nitrate record about 2.2 miles out from the town centreFederal environmental registers
- San Luis's boundary and the 21,646 acres inside itUS Census TIGER/Line 2025
- The ecoregion at San Luis's own centroid, the Sonoran Basin and RangeUS EPA Level III Ecoregions
- Lanternfly survey cells around San Luis checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — San Luis 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 San Luis's 21,646 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 San Luis's 21,646 acreswhy one lot differs from the next →
- Which side of San Luis you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 21,646 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 2.2 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 San Luis-wide figureread your own land →