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

Planting zone for 75661 — Karnack, TX

ZIP code 75661 (Karnack, Harrison County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 6 and the first fall frost November 19.

Where ZIP 75661 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.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostMar 6

First frostNov 19

2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Karnack, 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 Karnack, 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 27only 10% chance of frost after

First fall frostNovember 19median — 10% chance by Nov 2

Growing season257 daysfrost-free, median

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

From the NOAA station Mooringsport 1 N, LA — 12 miles away, elevation 200 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 75661

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 24 – Oct 8

GarlicPlant cloves · Nov 5 – Dec 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 6) and first fall frost (Nov 19) 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 75661 came on Feb 8 — 4 days later than the 1991–2020 average (Feb 4).

average
Feb 42026
Feb 8

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 8b in Texas

620 plants native to the lower 48 states, recorded in Texas, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. 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 Karnack, TX.

Soil in Karnack, TX

The soil mapped at the center of ZIP 75661 is Eastwood — very fine sandy loam, well drained.

TextureVery fine sandy loamdrains and warms fast; dries out and needs more feeding

pH5.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Eastwood very fine sandy loam, 5 to 20 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 75661; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Karnack, TX

Summer high94 °Faverage high, July

Winter low35 °Faverage low, January

Hot days87days a year at 90 °F or more

Freezing nights35nights a year at 32 °F or less

Growing degree days6,162base 50 °F — the season’s usable heat

Longest day14 h 18 mindaylight on June 21

Shortest day10 h 00 mindaylight on December 21

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

Precipitation50.8 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: Mooringsport 1 N, LA (12 mi away); precipitation: Mooringsport 1 N, LA (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8b.

756888b

Scottsville, TX · 8 mi

710608b

Mooringsport, LA · 10 mi

756598b

Jonesville, TX · 10 mi

Jefferson, TX · 14 mi

Texas planting zones →

Questions about 75661

What planting zone is ZIP code 75661?

ZIP code 75661 (Karnack, TX) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Karnack, TX?

The median last spring frost (32 °F) near 75661 is March 6; after March 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mooringsport 1 N station.

When is the first frost in Karnack, TX?

The median first fall frost near 75661 is November 19, giving a median frost-free growing season of 257 days.

When should I plant tomatoes in 75661?

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 75661 get?

About 50.8 inches of precipitation a year (NOAA 1991–2020 normals, Mooringsport 1 N station).

How hot do summers get in Karnack, TX?

The average high peaks at 94 °F in July, with about 87 days a year at 90 °F or more.

What kind of soil does 75661 have?

The USDA soil survey maps Eastwood at the center of ZIP 75661: very fine sandy loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Karnack, TX in 2026?

Spring leaf-out near 75661 came on Feb 8 in 2026, 4 days later than the 1991–2020 average (Feb 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Karnack, TX?

Short-day onions: the longest day near 75661 is 14 h 18 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.