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

Planting zone for 78879 — Rio Frio, TX

ZIP code 78879 (Rio Frio, Real County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is March 12 and the first fall frost November 14.

Where ZIP 78879 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 12

First frostNov 14

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 Rio Frio, 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 Rio Frio, TX

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 12median — 50% chance of a later frost

Safe for tender plantsApril 2only 10% chance of frost after

First fall frostNovember 14median — 10% chance by Oct 30

Growing season248 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 1 and returns around November 27.

From the NOAA station Camp Wood, TX — 18 miles away, elevation 1,480 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 78879

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 29 – Feb 12

SpinachSow outdoors · Jan 29 – Feb 19

Broccoli, cabbageStart indoors · Jan 1 – Jan 15

Broccoli, cabbageTransplant · Feb 19 – Mar 5

Onion setsPlant outdoors · Feb 12 – Feb 26

PotatoesPlant outdoors · Feb 19 – Mar 5

LettuceSow outdoors · Feb 12 – Feb 26

Carrots, beetsSow outdoors · Feb 19 – Mar 5

TomatoesStart indoors · Jan 15 – Jan 29

TomatoesTransplant · Mar 19 – Apr 2

Peppers, eggplantStart indoors · Jan 1 – Jan 15

Peppers, eggplantTransplant · Mar 26 – Apr 9

BeansSow outdoors · Mar 19 – Apr 2

Sweet cornSow outdoors · Mar 19 – Apr 2

Cucumbers, squashSow outdoors · Mar 19 – Apr 2

Fall lettuce, spinachSow outdoors · Sep 19 – Oct 3

GarlicPlant cloves · Oct 31 – Dec 5

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 12) and first fall frost (Nov 14) 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 78879 came on Feb 2 — 3 days later than the 1991–2020 average (Jan 30).

average
Jan 302026
Feb 2

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 Rio Frio, TX.

Soil in Rio Frio, TX

The soil mapped at the center of ZIP 78879 is Eckrant — very cobbly silty clay, well drained.

TextureVery cobbly silty clayholds water and nutrients; slow to drain and warm up

pH7.3neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter6%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Eckrant-Rock outcrop complex, 15 to 60 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 78879; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rio Frio, TX

Summer high95 °Faverage high, August

Winter low35 °Faverage low, January

Hot days102days a year at 90 °F or more

Freezing nights48nights a year at 32 °F or less

Growing degree days6,513base 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

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: Camp Wood, TX (18 mi away); precipitation: Leakey 1.5 Ene, TX (6 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.

Vanderpool, TX · 16 mi

788338b

Camp Wood, TX · 16 mi

Texas planting zones →

Questions about 78879

What planting zone is ZIP code 78879?

ZIP code 78879 (Rio Frio, 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 Rio Frio, TX?

The median last spring frost (32 °F) near 78879 is March 12; after April 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Camp Wood station.

When is the first frost in Rio Frio, TX?

The median first fall frost near 78879 is November 14, giving a median frost-free growing season of 248 days.

When should I plant tomatoes in 78879?

Start tomato seeds indoors around Jan 15 – Jan 29 and set transplants outside around Mar 19 – Apr 2, one to three weeks after the median last frost.

How much rain and snow does 78879 get?

About 31.5 inches of precipitation a year (NOAA 1991–2020 normals, Leakey 1.5 Ene station).

How hot do summers get in Rio Frio, TX?

The average high peaks at 95 °F in August, with about 102 days a year at 90 °F or more.

What kind of soil does 78879 have?

The USDA soil survey maps Eckrant at the center of ZIP 78879: very cobbly silty clay, well drained, pH about 7.3 (neutral).

Did spring come early in Rio Frio, TX in 2026?

Spring leaf-out near 78879 came on Feb 2 in 2026, 3 days later than the 1991–2020 average (Jan 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rio Frio, TX?

Short-day onions: the longest day near 78879 is 14 h 03 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.