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

Planting zone for 78638 — Kingsbury, TX

ZIP code 78638 (Kingsbury, Guadalupe County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 5 and the first fall frost November 23.

Where ZIP 78638 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 5

First frostNov 23

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 Kingsbury, 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 Kingsbury, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 5median — 50% chance of a later frost

Safe for tender plantsApril 3only 10% chance of frost after

First fall frostNovember 23median — 10% chance by Nov 3

Growing season263 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 17 and returns around December 6.

From the NOAA station Luling, TX — 7 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 78638

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 22 – Feb 5

SpinachSow outdoors · Jan 22 – Feb 12

Broccoli, cabbageStart indoors · Dec 25 – Jan 8

Broccoli, cabbageTransplant · Feb 12 – Feb 26

Onion setsPlant outdoors · Feb 5 – Feb 19

PotatoesPlant outdoors · Feb 12 – Feb 26

LettuceSow outdoors · Feb 5 – Feb 19

Carrots, beetsSow outdoors · Feb 12 – Feb 26

TomatoesStart indoors · Jan 8 – Jan 22

TomatoesTransplant · Mar 12 – Mar 26

Peppers, eggplantStart indoors · Dec 25 – Jan 8

Peppers, eggplantTransplant · Mar 19 – Apr 2

BeansSow outdoors · Mar 12 – Mar 26

Sweet cornSow outdoors · Mar 12 – Mar 26

Cucumbers, squashSow outdoors · Mar 12 – Mar 26

Fall lettuce, spinachSow outdoors · Sep 28 – Oct 12

GarlicPlant cloves · Nov 9 – Dec 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 5) and first fall frost (Nov 23) 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 78638 came on Jan 29 — 3 days later than the 1991–2020 average (Jan 26).

average
Jan 262026
Jan 29

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 Kingsbury, TX.

Soil in Kingsbury, TX

The soil mapped at the center of ZIP 78638 is Crockett — fine sandy loam, moderately well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH6.5neutral; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter1.25%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Crockett fine sandy loam, 1 to 3 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 78638; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Kingsbury, TX

Summer high98 °Faverage high, August

Winter low40 °Faverage low, January

Hot days118days a year at 90 °F or more

Freezing nights29nights a year at 32 °F or less

Growing degree days7,375base 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

Precipitation34 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: Luling, TX (7 mi away); precipitation: Kingsbury, TX (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9a.

786619a

Prairie Lea, TX · 5 mi

Martindale, TX · 11 mi

781569a

Seguin, TX · 12 mi

Texas planting zones →

Questions about 78638

What planting zone is ZIP code 78638?

ZIP code 78638 (Kingsbury, 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 Kingsbury, TX?

The median last spring frost (32 °F) near 78638 is March 5; after April 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Luling station.

When is the first frost in Kingsbury, TX?

The median first fall frost near 78638 is November 23, giving a median frost-free growing season of 263 days.

When should I plant tomatoes in 78638?

Start tomato seeds indoors around Jan 8 – Jan 22 and set transplants outside around Mar 12 – Mar 26, one to three weeks after the median last frost.

How much rain and snow does 78638 get?

About 34 inches of precipitation a year (NOAA 1991–2020 normals, Kingsbury station).

How hot do summers get in Kingsbury, TX?

The average high peaks at 98 °F in August, with about 118 days a year at 90 °F or more.

What kind of soil does 78638 have?

The USDA soil survey maps Crockett at the center of ZIP 78638: fine sandy loam, moderately well drained, pH about 6.5 (neutral).

Did spring come early in Kingsbury, TX in 2026?

Spring leaf-out near 78638 came on Jan 29 in 2026, 3 days later than the 1991–2020 average (Jan 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Kingsbury, TX?

Short-day onions: the longest day near 78638 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 78638 change?

Yes. The 2012 USDA map put 78638 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.