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

Planting zone for 78156 — Seguin, TX

ZIP code 78156 (Seguin, Guadalupe County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 1 and the first fall frost November 26.

Where ZIP 78156 is

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 1

First frostNov 26

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 Seguin, 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 Seguin, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 1median — 50% chance of a later frost

Safe for tender plantsMarch 20only 10% chance of frost after

First fall frostNovember 26median — 10% chance by Nov 8

Growing season273 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 13 and returns around December 11.

From the NOAA station Austin San Antonio, TX — 7 miles away, elevation 633 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 78156

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 18 – Feb 1

SpinachSow outdoors · Jan 18 – Feb 8

Broccoli, cabbageStart indoors · Dec 21 – Jan 4

Broccoli, cabbageTransplant · Feb 8 – Feb 22

Onion setsPlant outdoors · Feb 1 – Feb 15

PotatoesPlant outdoors · Feb 8 – Feb 22

LettuceSow outdoors · Feb 1 – Feb 15

Carrots, beetsSow outdoors · Feb 8 – Feb 22

TomatoesStart indoors · Jan 4 – Jan 18

TomatoesTransplant · Mar 8 – Mar 22

Peppers, eggplantStart indoors · Dec 21 – Jan 4

Peppers, eggplantTransplant · Mar 15 – Mar 29

BeansSow outdoors · Mar 8 – Mar 22

Sweet cornSow outdoors · Mar 8 – Mar 22

Cucumbers, squashSow outdoors · Mar 8 – Mar 22

Fall lettuce, spinachSow outdoors · Oct 1 – Oct 15

GarlicPlant cloves · Nov 12 – Dec 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 1) and first fall frost (Nov 26) 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 78156 came on Jan 20 — 5 days earlier than the 1991–2020 average (Jan 25).

average
Jan 252026
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 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 Seguin, TX.

Soil in Seguin, TX

The soil mapped at the center of ZIP 78156 is Branyon — clay, moderately well drained.

TextureClayholds water and nutrients; slow to drain and warm up

pH7.8slightly alkaline; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter2%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classprime farmlandUSDA classification

Map unit: Branyon 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 78156; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Seguin, TX

Summer high98 °Faverage high, August

Winter low40 °Faverage low, January

Hot days128days a year at 90 °F or more

Freezing nights20nights a year at 32 °F or less

Growing degree days7,389base 50 °F — the season’s usable heat

Longest day14 h 03 mindaylight on June 21

Shortest day10 h 14 mindaylight on December 21

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

Precipitation35.8 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: Austin San Antonio, TX (7 mi away); precipitation: Mcqueeney 0.5 Ene, TX (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9a.

781239a

Mc Queeney, TX · 4 mi

New Braunfels, TX · 8 mi

781319a

New Braunfels, TX · 11 mi

781359a

New Braunfels, TX · 11 mi

781249a

Marion, TX · 11 mi

786389a

Kingsbury, TX · 12 mi

All 2 ZIP codes in Seguin → · Texas planting zones →

Questions about 78156

What planting zone is ZIP code 78156?

ZIP code 78156 (Seguin, 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 Seguin, TX?

The median last spring frost (32 °F) near 78156 is March 1; after March 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Austin San Antonio station.

When is the first frost in Seguin, TX?

The median first fall frost near 78156 is November 26, giving a median frost-free growing season of 273 days.

When should I plant tomatoes in 78156?

Start tomato seeds indoors around Jan 4 – Jan 18 and set transplants outside around Mar 8 – Mar 22, one to three weeks after the median last frost.

How much rain and snow does 78156 get?

About 35.8 inches of precipitation a year (NOAA 1991–2020 normals, Mcqueeney 0.5 Ene station).

How hot do summers get in Seguin, TX?

The average high peaks at 98 °F in August, with about 128 days a year at 90 °F or more.

What kind of soil does 78156 have?

The USDA soil survey maps Branyon at the center of ZIP 78156: clay, moderately well drained, pH about 7.8 (slightly alkaline).

Did spring come early in Seguin, TX in 2026?

Spring leaf-out near 78156 came on Jan 20 in 2026, 5 days earlier than the 1991–2020 average (Jan 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Seguin, TX?

Short-day onions: the longest day near 78156 is 14 h 03 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 78156 change?

Yes. The 2012 USDA map put 78156 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.