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

Planting zone for 79842 — Marathon, TX

ZIP code 79842 (Marathon, Brewster County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 7 and the first fall frost November 1.

Where ZIP 79842 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 frostApr 7

First frostNov 1

2012 zone8a

Was 8a 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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Marathon, 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 Marathon, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 7median — 50% chance of a later frost

Safe for tender plantsApril 26only 10% chance of frost after

First fall frostNovember 1median — 10% chance by Oct 18

Growing season205 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 20 and returns around November 8.

From the NOAA station Marathon, TX — 19 miles away, elevation 3,990 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 79842

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 24 – Mar 10

SpinachSow outdoors · Feb 24 – Mar 17

Broccoli, cabbageStart indoors · Jan 27 – Feb 10

Broccoli, cabbageTransplant · Mar 17 – Mar 31

Onion setsPlant outdoors · Mar 10 – Mar 24

PotatoesPlant outdoors · Mar 17 – Mar 31

LettuceSow outdoors · Mar 10 – Mar 24

Carrots, beetsSow outdoors · Mar 17 – Mar 31

TomatoesStart indoors · Feb 10 – Feb 24

TomatoesTransplant · Apr 14 – Apr 28

Peppers, eggplantStart indoors · Jan 27 – Feb 10

Peppers, eggplantTransplant · Apr 21 – May 5

BeansSow outdoors · Apr 14 – Apr 28

Sweet cornSow outdoors · Apr 14 – Apr 28

Cucumbers, squashSow outdoors · Apr 14 – Apr 28

Fall lettuce, spinachSow outdoors · Sep 6 – Sep 20

GarlicPlant cloves · Oct 18 – Nov 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Nov 1) 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 79842 came on Feb 5 — 4 days later than the 1991–2020 average (Feb 1).

average
Feb 12026
Feb 5

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 Marathon, TX.

Soil in Marathon, TX

The soil mapped at the center of ZIP 79842 is Coyanosa — extremely gravelly fine sandy loam, well drained.

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

pH7.5slightly alkaline; 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: Coyanosa-Buckear-Rock outcrop complex, 20 to 45 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 79842; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Marathon, TX

Summer high92 °Faverage high, June

Winter low27 °Faverage low, January

Hot days95days a year at 90 °F or more

Freezing nights75nights a year at 32 °F or less

Growing degree days4,889base 50 °F — the season’s usable heat

Longest day14 h 05 mindaylight on June 21

Shortest day10 h 13 mindaylight on December 21

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

Precipitation12.6 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: Marathon, TX (19 mi away); precipitation: Marathon, TX (19 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

798308b

Alpine, TX · 38 mi

798488b

Sanderson, TX · 38 mi

798318a

Alpine, TX · 43 mi

797358b

Fort Stockton, TX · 54 mi

798529a

Terlingua, TX · 57 mi

798468b

Redford, TX · 72 mi

797348a

Fort Davis, TX · 73 mi

797868a

Toyahvale, TX · 79 mi

Texas planting zones →

Questions about 79842

What planting zone is ZIP code 79842?

ZIP code 79842 (Marathon, 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 Marathon, TX?

The median last spring frost (32 °F) near 79842 is April 7; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Marathon station.

When is the first frost in Marathon, TX?

The median first fall frost near 79842 is November 1, giving a median frost-free growing season of 205 days.

When should I plant tomatoes in 79842?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 79842 get?

About 12.6 inches of precipitation a year (NOAA 1991–2020 normals, Marathon station).

How hot do summers get in Marathon, TX?

The average high peaks at 92 °F in June, with about 95 days a year at 90 °F or more.

What kind of soil does 79842 have?

The USDA soil survey maps Coyanosa at the center of ZIP 79842: extremely gravelly fine sandy loam, well drained, pH about 7.5 (slightly alkaline).

Did spring come early in Marathon, TX in 2026?

Spring leaf-out near 79842 came on Feb 5 in 2026, 4 days later than the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Marathon, TX?

Short-day onions: the longest day near 79842 is 14 h 05 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 79842 change?

Yes. The 2012 USDA map put 79842 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.