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

Planting zone for 77989 — Thomaston, TX

ZIP code 77989 (Thomaston, DeWitt County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is February 14 and the first fall frost December 9.

Where ZIP 77989 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 frostFeb 14

First frostDec 9

2012 zone9a

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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Thomaston, 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 Thomaston, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 14median — 50% chance of a later frost

Safe for tender plantsMarch 13only 10% chance of frost after

First fall frostDecember 9median — 10% chance by Nov 17

Growing season299 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 28 and returns around December 31.

From the NOAA station Victoria Fire Dept #5, TX — 12 miles away, elevation 102 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 77989

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 3 – Jan 17

SpinachSow outdoors · Jan 3 – Jan 24

Broccoli, cabbageStart indoors · Dec 6 – Dec 20

Broccoli, cabbageTransplant · Jan 24 – Feb 7

Onion setsPlant outdoors · Jan 17 – Jan 31

PotatoesPlant outdoors · Jan 24 – Feb 7

LettuceSow outdoors · Jan 17 – Jan 31

Carrots, beetsSow outdoors · Jan 24 – Feb 7

TomatoesStart indoors · Dec 20 – Jan 3

TomatoesTransplant · Feb 21 – Mar 7

Peppers, eggplantStart indoors · Dec 6 – Dec 20

Peppers, eggplantTransplant · Feb 28 – Mar 14

BeansSow outdoors · Feb 21 – Mar 7

Sweet cornSow outdoors · Feb 21 – Mar 7

Cucumbers, squashSow outdoors · Feb 21 – Mar 7

Fall lettuce, spinachSow outdoors · Oct 14 – Oct 28

GarlicPlant cloves · Nov 25 – Dec 30

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 14) and first fall frost (Dec 9) 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 77989 came on Jan 15 — 8 days earlier than the 1991–2020 average (Jan 23).

average
Jan 232026
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 Thomaston, TX.

Soil in Thomaston, TX

The soil mapped at the center of ZIP 77989 is Tremona — loamy fine sand, somewhat poorly drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Tremona loamy fine sand, 1 to 5 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 77989; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Thomaston, TX

Summer high94 °Faverage high, August

Winter low42 °Faverage low, January

Hot days116days a year at 90 °F or more

Freezing nights14nights a year at 32 °F or less

Growing degree days7,504base 50 °F — the season’s usable heat

Longest day14 h 00 mindaylight on June 21

Shortest day10 h 17 mindaylight on December 21

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

Precipitation38.5 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: Victoria Fire Dept #5, TX (12 mi away); precipitation: Cuero 2.6 Ese, TX (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Meyersville, TX · 11 mi

Texas planting zones →

Questions about 77989

What planting zone is ZIP code 77989?

ZIP code 77989 (Thomaston, 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 Thomaston, TX?

The median last spring frost (32 °F) near 77989 is February 14; after March 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Victoria Fire Dept #5 station.

When is the first frost in Thomaston, TX?

The median first fall frost near 77989 is December 9, giving a median frost-free growing season of 299 days.

When should I plant tomatoes in 77989?

Start tomato seeds indoors around Dec 20 – Jan 3 and set transplants outside around Feb 21 – Mar 7, one to three weeks after the median last frost.

How much rain and snow does 77989 get?

About 38.5 inches of precipitation a year (NOAA 1991–2020 normals, Cuero 2.6 Ese station).

How hot do summers get in Thomaston, TX?

The average high peaks at 94 °F in August, with about 116 days a year at 90 °F or more.

What kind of soil does 77989 have?

The USDA soil survey maps Tremona at the center of ZIP 77989: loamy fine sand, somewhat poorly drained, pH about 5.8 (moderately acidic).

Did spring come early in Thomaston, TX in 2026?

Spring leaf-out near 77989 came on Jan 15 in 2026, 8 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Thomaston, TX?

Short-day onions: the longest day near 77989 is 14 h 00 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.