Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 85349 — San Luis, AZ

ZIP code 85349 (San Luis, Yuma County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 85349 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostrare
First frostrare
2012 zone10a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for San Luis, AZ…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station Yuma Quartermaster Depot, AZ — 18 miles away, elevation 161 ft) the median growing season is 362 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 85349 came on Jan 18 — 3 days earlier than the 1991–2020 average (Jan 21).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 10a in Arizona

506 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 30 °F or colder — the bottom of zone 10a. Each links to its USDA PLANTS profile.

Trees 27

Arizona cypress50 ft · blooms spring · low shade tolerance · to −23 °FArizona madrone30 ft · blooms late spring · high shade tolerance · to −4 °FArizona sycamore80 ft · blooms early spring · high shade tolerance · to −8 °FArizona walnut50 ft · blooms late spring · high shade tolerance · to −33 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °F

Shrubs 118

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican tarwort3 ft · blooms late spring · high shade tolerance · to −23 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FApache plume6 ft · blooms late spring · high shade tolerance · to −23 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 199

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican century plant6 ft · blooms indeterminate · high shade tolerance · to 12 °F

Grasses 153

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °FArizona cottontop4 ft · blooms late summer · high shade tolerance · to −13 °FArizona fescue2 ft · blooms late spring · high shade tolerance · to −23 °F

Vines 1

western white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in San Luis, AZ.

Soil in San Luis, AZ

The soil mapped at the center of ZIP 85349 is Rositas — sand, somewhat excessively drained.

TextureSanddrains and warms fast; dries out and needs more feeding
pH8.2alkaline; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.25%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classFarmland of unique importanceUSDA classification

Map unit: Rositas sand.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 85349; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Luis, AZ

Summer high107 °Faverage high, July
Winter low47 °Faverage low, December
Hot days181days a year at 90 °F or more
Freezing nights0nights a year at 32 °F or less
Growing degree days9,509base 50 °F — the season’s usable heat
Longest day14 h 17 mindaylight on June 21
Shortest day10 h 01 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation3.3 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°90°100°110°120°January: average high 70 °F, low 48 °F 70°48° JanFebruary: average high 73 °F, low 50 °F 73°50° FebMarch: average high 80 °F, low 55 °F 80°55° MarApril: average high 86 °F, low 60 °F 86°60° AprMay: average high 94 °F, low 67 °F 94°67° MayJune: average high 103 °F, low 75 °F 103°75° JunJuly: average high 107 °F, low 83 °F 107°83° JulAugust: average high 106 °F, low 83 °F 106°83° AugSeptember: average high 101 °F, low 78 °F 101°78° SepOctober: average high 90 °F, low 66 °F 90°66° OctNovember: average high 78 °F, low 54 °F 78°54° NovDecember: average high 68 °F, low 47 °F 68°47° Dec

Precipitation by month inches

0″1″January: 0.39 in precipitation 0.4 JanFebruary: 0.38 in precipitation 0.4 FebMarch: 0.39 in precipitation 0.4 MarApril: 0.14 in precipitation 0.1 AprMay: 0.06 in precipitation 0.1 MayJune: 0.01 in precipitation 0.0 JunJuly: 0.24 in precipitation 0.2 JulAugust: 0.20 in precipitation 0.2 AugSeptember: 0.68 in precipitation 0.7 SepOctober: 0.13 in precipitation 0.1 OctNovember: 0.23 in precipitation 0.2 NovDecember: 0.43 in precipitation 0.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Yuma Mcas, AZ (12 mi away); precipitation: Yuma Mcas, AZ (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10a.

8533610a
Gadsden, AZ · 4 mi
8535010a
Somerton, AZ · 6 mi
8536610a
Yuma, AZ · 10 mi
8536410a
Yuma, AZ · 16 mi
8536910a
Yuma, AZ · 18 mi
8536710a
Yuma, AZ · 21 mi
9222210a
Bard, CA · 23 mi
9228310a
Winterhaven, CA · 29 mi

Arizona planting zones →

Questions about 85349

What planting zone is ZIP code 85349?

ZIP code 85349 (San Luis, AZ) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

How much rain and snow does 85349 get?

About 3.3 inches of precipitation a year (NOAA 1991–2020 normals, Yuma Mcas station).

How hot do summers get in San Luis, AZ?

The average high peaks at 107 °F in July, with about 181 days a year at 90 °F or more.

What kind of soil does 85349 have?

The USDA soil survey maps Rositas at the center of ZIP 85349: sand, somewhat excessively drained, pH about 8.2 (alkaline).

Did spring come early in San Luis, AZ in 2026?

Spring leaf-out near 85349 came on Jan 18 in 2026, 3 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in San Luis, AZ?

Short-day onions: the longest day near 85349 is 14 h 17 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.