Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 78121 — La Vernia, TX

ZIP code 78121 (La Vernia, Wilson County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 6 and the first fall frost November 20.

Where ZIP 78121 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.

Zone9a20 to 25 °F

Coldest night−6.7 to −3.9 °C

Last frostMar 6

First frostNov 20

2012 zone8b

Was 8b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for La Vernia, 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 in La Vernia, TX

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMarch 6median — 50% chance of a later frost

Safe for tender plantsMarch 30only 10% chance of frost after

First fall frostNovember 20median — 10% chance by Nov 2

Growing season261 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 21 and returns around December 3.

From the NOAA station Floresville, TX — 16 miles away, elevation 400 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 78121

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 23 – Feb 6

SpinachSow outdoors · Jan 23 – Feb 13

Broccoli, cabbageStart indoors · Dec 26 – Jan 9

Broccoli, cabbageTransplant · Feb 13 – Feb 27

Onion setsPlant outdoors · Feb 6 – Feb 20

PotatoesPlant outdoors · Feb 13 – Feb 27

LettuceSow outdoors · Feb 6 – Feb 20

Carrots, beetsSow outdoors · Feb 13 – Feb 27

TomatoesStart indoors · Jan 9 – Jan 23

TomatoesTransplant · Mar 13 – Mar 27

Peppers, eggplantStart indoors · Dec 26 – Jan 9

Peppers, eggplantTransplant · Mar 20 – Apr 3

BeansSow outdoors · Mar 13 – Mar 27

Sweet cornSow outdoors · Mar 13 – Mar 27

Cucumbers, squashSow outdoors · Mar 13 – Mar 27

Fall lettuce, spinachSow outdoors · Sep 25 – Oct 9

GarlicPlant cloves · Nov 6 – Dec 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 6) and first fall frost (Nov 20) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 78121 came on Jan 15 — 9 days earlier than the 1991–2020 average (Jan 24).

average
Jan 242026
Jan 15

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 9a in Texas

640 plants native to the lower 48 states, recorded in Texas, and rated by the USDA to survive 20 °F or colder — the bottom of zone 9a. Each links to its USDA PLANTS profile.

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 La Vernia, TX.

Soil in La Vernia, TX

The soil mapped at the center of ZIP 78121 is Buchel — clay, moderately well drained.

TextureClayholds water and nutrients; slow to drain and warm up

pH8.1alkaline; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter1.75%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Buchel clay, 0 to 1 percent slopes, occasionally flooded.

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 78121; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in La Vernia, TX

Summer high98 °Faverage high, August

Winter low39 °Faverage low, January

Hot days130days a year at 90 °F or more

Freezing nights27nights a year at 32 °F or less

Growing degree days7,407base 50 °F — the season’s usable heat

Longest day14 h 02 mindaylight on June 21

Shortest day10 h 16 mindaylight on December 21

Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb

Precipitation35.4 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Floresville, TX (16 mi away); precipitation: La Vernia 3.0 E, TX (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9a.

781619a

Sutherland Springs, TX · 5 mi

781529a

Saint Hedwig, TX · 9 mi

781019a

Adkins, TX · 9 mi

781609a

Stockdale, TX · 13 mi

782639a

San Antonio, TX · 14 mi

Texas planting zones →

Questions about 78121

What planting zone is ZIP code 78121?

ZIP code 78121 (La Vernia, TX) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in La Vernia, TX?

The median last spring frost (32 °F) near 78121 is March 6; after March 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Floresville station.

When is the first frost in La Vernia, TX?

The median first fall frost near 78121 is November 20, giving a median frost-free growing season of 261 days.

When should I plant tomatoes in 78121?

Start tomato seeds indoors around Jan 9 – Jan 23 and set transplants outside around Mar 13 – Mar 27, one to three weeks after the median last frost.

How much rain and snow does 78121 get?

About 35.4 inches of precipitation a year (NOAA 1991–2020 normals, La Vernia 3.0 E station).

How hot do summers get in La Vernia, TX?

The average high peaks at 98 °F in August, with about 130 days a year at 90 °F or more.

What kind of soil does 78121 have?

The USDA soil survey maps Buchel at the center of ZIP 78121: clay, moderately well drained, pH about 8.1 (alkaline).

Did spring come early in La Vernia, TX in 2026?

Spring leaf-out near 78121 came on Jan 15 in 2026, 9 days earlier than the 1991–2020 average (Jan 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in La Vernia, TX?

Short-day onions: the longest day near 78121 is 14 h 02 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 78121 change?

Yes. The 2012 USDA map put 78121 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.