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

Planting zone for 78391 — Tynan, TX

ZIP code 78391 (Tynan, Bee County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 1 and the first fall frost December 17.

Where ZIP 78391 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 frostFeb 1

First frostDec 17

2012 zone9a

Was 9a 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 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tynan, 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 Tynan, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

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

Safe for tender plantsMarch 6only 10% chance of frost after

First fall frostDecember 17median — 10% chance by Nov 22

Growing season324 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 12 and returns around January 1.

From the NOAA station Sinton, TX — 14 miles away, elevation 49 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 78391

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Dec 21 – Jan 4

SpinachSow outdoors · Dec 21 – Jan 11

Broccoli, cabbageStart indoors · Nov 23 – Dec 7

Broccoli, cabbageTransplant · Jan 11 – Jan 25

Onion setsPlant outdoors · Jan 4 – Jan 18

PotatoesPlant outdoors · Jan 11 – Jan 25

LettuceSow outdoors · Jan 4 – Jan 18

Carrots, beetsSow outdoors · Jan 11 – Jan 25

TomatoesStart indoors · Dec 7 – Dec 21

TomatoesTransplant · Feb 8 – Feb 22

Peppers, eggplantStart indoors · Nov 23 – Dec 7

Peppers, eggplantTransplant · Feb 15 – Mar 1

BeansSow outdoors · Feb 8 – Feb 22

Sweet cornSow outdoors · Feb 8 – Feb 22

Cucumbers, squashSow outdoors · Feb 8 – Feb 22

Fall lettuce, spinachSow outdoors · Oct 22 – Nov 5

GarlicPlant cloves · Dec 3 – Jan 7

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 1) and first fall frost (Dec 17) 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 78391 came on Jan 10 — 10 days earlier than the 1991–2020 average (Jan 20).

average
Jan 202026
Jan 10

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.

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 Tynan, TX.

Soil in Tynan, TX

The soil mapped at the center of ZIP 78391 is Orelia — fine sandy loam, well drained.

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

pH6.6neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.3%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Orelia fine sandy loam, 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 78391; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tynan, TX

Summer high95 °Faverage high, August

Winter low45 °Faverage low, January

Hot days113days a year at 90 °F or more

Freezing nights7nights a year at 32 °F or less

Growing degree days7,999base 50 °F — the season’s usable heat

Longest day13 h 56 mindaylight on June 21

Shortest day10 h 21 mindaylight on December 21

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

Precipitation31.5 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: Sinton, TX (14 mi away); precipitation: Beeville 9.0 S, TX (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

Texas planting zones →

Questions about 78391

What planting zone is ZIP code 78391?

ZIP code 78391 (Tynan, 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).

When is the last frost in Tynan, TX?

The median last spring frost (32 °F) near 78391 is February 1; after March 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sinton station.

When is the first frost in Tynan, TX?

The median first fall frost near 78391 is December 17, giving a median frost-free growing season of 324 days.

When should I plant tomatoes in 78391?

Start tomato seeds indoors around Dec 7 – Dec 21 and set transplants outside around Feb 8 – Feb 22, one to three weeks after the median last frost.

How much rain and snow does 78391 get?

About 31.5 inches of precipitation a year (NOAA 1991–2020 normals, Beeville 9.0 S station).

How hot do summers get in Tynan, TX?

The average high peaks at 95 °F in August, with about 113 days a year at 90 °F or more.

What kind of soil does 78391 have?

The USDA soil survey maps Orelia at the center of ZIP 78391: fine sandy loam, well drained, pH about 6.6 (neutral).

Did spring come early in Tynan, TX in 2026?

Spring leaf-out near 78391 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 Tynan, TX?

Short-day onions: the longest day near 78391 is 13 h 56 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 78391 change?

Yes. The 2012 USDA map put 78391 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.