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

Planting zone for 78380 — Robstown, TX

ZIP code 78380 (Robstown, Nueces County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F.

Where ZIP 78380 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.

Zone9b25 to 30 °F
Coldest night−3.9 to −1.1 °C
Last frostrare
First frostrare
2012 zone9b

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 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Robstown, TX…

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 Robstown, TX — 5 miles away, elevation 85 ft) the median growing season is 336 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 78380 came on Jan 10 — 10 days earlier than the 1991–2020 average (Jan 20).

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 9b in Texas

646 plants native to the lower 48 states, recorded in Texas, and rated by the USDA to survive 25 °F or colder — the bottom of zone 9b. Each links to its USDA PLANTS profile.

Trees 72

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °FArizona cypress50 ft · blooms spring · low shade tolerance · to −23 °FArizona walnut50 ft · blooms late spring · high shade tolerance · to −33 °F

Shrubs 142

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Faloe yucca15 ft · blooms early summer · medium shade tolerance · to −1 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °FAmerican snowbell10 ft · blooms spring · medium shade tolerance · to −16 °F

Wildflowers & perennials 212

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican century plant6 ft · blooms indeterminate · high shade tolerance · to 12 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °F

Grasses 197

alkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °FArizona cottontop4 ft · blooms late summer · high shade tolerance · to −13 °FArizona fescue2 ft · blooms late spring · high shade tolerance · to −23 °FArizona threeawn2 ft · blooms mid summer · high shade tolerance · to −3 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °F

Vines 14

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °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 Robstown, TX.

Soil in Robstown, TX

The soil mapped at the center of ZIP 78380 is Victoria — clay, well drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH8.1alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Victoria clay 0 to 1 percent slopes.

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 78380; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Robstown, TX

Summer high96 °Faverage high, August
Winter low47 °Faverage low, January
Hot days124days a year at 90 °F or more
Freezing nights4nights a year at 32 °F or less
Growing degree days8,522base 50 °F — the season’s usable heat
Longest day13 h 54 mindaylight on June 21
Shortest day10 h 23 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation31.1 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°90°100°110°January: average high 68 °F, low 47 °F 68°47° JanFebruary: average high 72 °F, low 51 °F 72°51° FebMarch: average high 77 °F, low 57 °F 77°57° MarApril: average high 83 °F, low 64 °F 83°64° AprMay: average high 88 °F, low 70 °F 88°70° MayJune: average high 93 °F, low 75 °F 93°75° JunJuly: average high 95 °F, low 76 °F 95°76° JulAugust: average high 96 °F, low 76 °F 96°76° AugSeptember: average high 92 °F, low 72 °F 92°72° SepOctober: average high 86 °F, low 65 °F 86°65° OctNovember: average high 77 °F, low 56 °F 77°56° NovDecember: average high 70 °F, low 49 °F 70°49° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.54 in precipitation 1.5 JanFebruary: 1.50 in precipitation 1.5 FebMarch: 2.15 in precipitation 2.1 MarApril: 1.70 in precipitation 1.7 AprMay: 3.31 in precipitation 3.3 MayJune: 3.03 in precipitation 3.0 JunJuly: 2.75 in precipitation 2.8 JulAugust: 3.02 in precipitation 3.0 AugSeptember: 5.02 in precipitation 5.0 SepOctober: 3.27 in precipitation 3.3 OctNovember: 2.14 in precipitation 2.1 NovDecember: 1.67 in precipitation, 0.2 in snowfall 1.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Robstown, TX (5 mi away); precipitation: Robstown, TX (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

783399b
Banquete, TX · 4 mi
783519b
Driscoll, TX · 8 mi
784109b
Corpus Christi, TX · 10 mi
7847210a
Corpus Christi, TX · 10 mi
783439b
Bishop, TX · 10 mi
783309b
Agua Dulce, TX · 11 mi
783709b
Odem, TX · 14 mi
784069b
Corpus Christi, TX · 14 mi

Texas planting zones →

Questions about 78380

What planting zone is ZIP code 78380?

ZIP code 78380 (Robstown, TX) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

How much rain and snow does 78380 get?

About 31.1 inches of precipitation a year (NOAA 1991–2020 normals, Robstown station).

How hot do summers get in Robstown, TX?

The average high peaks at 96 °F in August, with about 124 days a year at 90 °F or more.

What kind of soil does 78380 have?

The USDA soil survey maps Victoria at the center of ZIP 78380: clay, well drained, pH about 8.1 (alkaline).

Did spring come early in Robstown, TX in 2026?

Spring leaf-out near 78380 came on Jan 10 in 2026, 10 days earlier than the 1991–2020 average (Jan 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Robstown, TX?

Short-day onions: the longest day near 78380 is 13 h 54 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.