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

Planting zone for Seneca, SC

Seneca, SC is in USDA zones 8a to 8b across its 3 ZIP codes. The median last spring frost is March 21 and the first fall frost November 11.

Seneca on the zone map

Outlined: its 2 ZIP code areas · 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.

Zones8a–8b10 to 20 °F
ZIP codes3
Last frostMar 21
First frostNov 11
Growing season236 days

8a 2 ZIPs   8b 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

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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 Seneca, SC

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 21median — 50% chance of a later frost
Safe for tender plantsApril 7only 10% chance of frost after
First fall frostNovember 11median — 10% chance by Oct 28
Growing season236 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 7 and returns around November 27.

From the NOAA station Clemson Oconee Co. Airport, SC, elevation 892 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 Seneca

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 7 – Feb 21
SpinachSow outdoors · Feb 7 – Feb 28
Broccoli, cabbageStart indoors · Jan 10 – Jan 24
Broccoli, cabbageTransplant · Feb 28 – Mar 14
Onion setsPlant outdoors · Feb 21 – Mar 7
PotatoesPlant outdoors · Feb 28 – Mar 14
LettuceSow outdoors · Feb 21 – Mar 7
Carrots, beetsSow outdoors · Feb 28 – Mar 14
TomatoesStart indoors · Jan 24 – Feb 7
TomatoesTransplant · Mar 28 – Apr 11
Peppers, eggplantStart indoors · Jan 10 – Jan 24
Peppers, eggplantTransplant · Apr 4 – Apr 18
BeansSow outdoors · Mar 28 – Apr 11
Sweet cornSow outdoors · Mar 28 – Apr 11
Cucumbers, squashSow outdoors · Mar 28 – Apr 11
Fall lettuce, spinachSow outdoors · Sep 16 – Sep 30
GarlicPlant cloves · Oct 28 – Dec 2
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 21) and first fall frost (Nov 11) 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 29679 came on Feb 18 — 6 days later than the 1991–2020 average (Feb 12).

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 8a in South Carolina

550 plants native to the lower 48 states, recorded in South Carolina, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. Each links to its USDA PLANTS profile.

Trees 82

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 126

Allegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Faloe yucca15 ft · blooms early summer · medium shade tolerance · to −1 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 163

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 158

alkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °F

Vines 12

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °F

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 Seneca, SC.

Soil in Seneca, SC

The soil mapped at the center of ZIP 29679 is Cecil — sandy loam, well drained.

TextureSandy 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 matter0.5%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Cecil sandy loam, 2 to 6 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 29679; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Seneca, SC

Summer high89 °Faverage high, July
Winter low34 °Faverage low, January
Hot days53days a year at 90 °F or more
Freezing nights38nights a year at 32 °F or less
Growing degree days4,946base 50 °F — the season’s usable heat
Longest day14 h 29 mindaylight on June 21
Shortest day9 h 50 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation58.8 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 52 °F, low 34 °F 52°34° JanFebruary: average high 56 °F, low 36 °F 56°36° FebMarch: average high 64 °F, low 43 °F 64°43° MarApril: average high 72 °F, low 50 °F 72°50° AprMay: average high 79 °F, low 59 °F 79°59° MayJune: average high 85 °F, low 66 °F 85°66° JunJuly: average high 89 °F, low 70 °F 89°70° JulAugust: average high 87 °F, low 69 °F 87°69° AugSeptember: average high 82 °F, low 64 °F 82°64° SepOctober: average high 72 °F, low 52 °F 72°52° OctNovember: average high 62 °F, low 42 °F 62°42° NovDecember: average high 54 °F, low 36 °F 54°36° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.72 in precipitation 5.7 JanFebruary: 4.80 in precipitation 4.8 FebMarch: 5.12 in precipitation 5.1 MarApril: 4.45 in precipitation 4.5 AprMay: 4.13 in precipitation 4.1 MayJune: 4.76 in precipitation 4.8 JunJuly: 4.94 in precipitation 4.9 JulAugust: 5.82 in precipitation 5.8 AugSeptember: 4.86 in precipitation 4.9 SepOctober: 4.20 in precipitation 4.2 OctNovember: 4.38 in precipitation 4.4 NovDecember: 5.58 in precipitation 5.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Clemson Oconee Co. Airport, SC (4 mi away); precipitation: Seneca 1.4 E, SC (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Seneca

296728a
10 to 15 °F
296788b
15 to 20 °F
296798a
10 to 15 °F

South Carolina planting zones →

Questions about Seneca

What planting zone is Seneca, SC?

Seneca, SC is in USDA hardiness zones 8a to 8b on the 2023 map (8a: 10 to 15 °F; 8b: 15 to 20 °F).

When is the last frost in Seneca, SC?

The median last spring frost is March 21 and the median first fall frost is November 11 (NOAA 1991–2020 normals, Clemson Oconee Co. Airport station).

When can I plant a garden in Seneca, SC?

Cool-season crops like peas and spinach go in around Feb 7 – Feb 28; tomatoes, peppers, beans and squash after about Mar 28, once frost risk has passed.

What kind of onions grow in Seneca, SC?

Intermediate onions: the longest day is 14 h 29 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Seneca, SC get?

About 58.8 inches of precipitation a year (NOAA 1991–2020 normals).