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

Planting zone for 29420 — North Charleston, SC

ZIP code 29420 (North Charleston, Dorchester County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 7 and the first fall frost November 27.

Where ZIP 29420 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.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostMar 7
First frostNov 27
2012 zone8b

Was 8b 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 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for North Charleston, SC…

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 North Charleston, SC

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 7median — 50% chance of a later frost
Safe for tender plantsMarch 27only 10% chance of frost after
First fall frostNovember 27median — 10% chance by Nov 8
Growing season266 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 20 and returns around December 15.

From the NOAA station Charleston Intl Airport, SC — 4 miles away, elevation 39 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 29420

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 24 – Feb 7
SpinachSow outdoors · Jan 24 – Feb 14
Broccoli, cabbageStart indoors · Dec 27 – Jan 10
Broccoli, cabbageTransplant · Feb 14 – Feb 28
Onion setsPlant outdoors · Feb 7 – Feb 21
PotatoesPlant outdoors · Feb 14 – Feb 28
LettuceSow outdoors · Feb 7 – Feb 21
Carrots, beetsSow outdoors · Feb 14 – Feb 28
TomatoesStart indoors · Jan 10 – Jan 24
TomatoesTransplant · Mar 14 – Mar 28
Peppers, eggplantStart indoors · Dec 27 – Jan 10
Peppers, eggplantTransplant · Mar 21 – Apr 4
BeansSow outdoors · Mar 14 – Mar 28
Sweet cornSow outdoors · Mar 14 – Mar 28
Cucumbers, squashSow outdoors · Mar 14 – Mar 28
Fall lettuce, spinachSow outdoors · Oct 2 – Oct 16
GarlicPlant cloves · Nov 13 – Dec 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 7) and first fall frost (Nov 27) 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 29420 came on Feb 3 — 3 days later than the 1991–2020 average (Jan 31).

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 9a in South Carolina

578 plants native to the lower 48 states, recorded in South Carolina, and rated by the USDA to survive 20 °F or colder — the bottom of zone 9a. Each links to its USDA PLANTS profile.

Trees 83

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 133

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 170

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 169

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 North Charleston, SC.

Soil in North Charleston, SC

The soil mapped at the center of ZIP 29420 is Wahee — fine sandy loam, somewhat poorly drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.3strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter2.75%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Wahee fine sandy loam.

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 29420; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in North Charleston, SC

Summer high91 °Faverage high, July
Winter low39 °Faverage low, January
Hot days64days a year at 90 °F or more
Freezing nights22nights a year at 32 °F or less
Growing degree days6,385base 50 °F — the season’s usable heat
Longest day14 h 20 mindaylight on June 21
Shortest day9 h 59 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation54.3 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 60 °F, low 39 °F 60°39° JanFebruary: average high 64 °F, low 42 °F 64°42° FebMarch: average high 70 °F, low 47 °F 70°47° MarApril: average high 77 °F, low 55 °F 77°55° AprMay: average high 84 °F, low 63 °F 84°63° MayJune: average high 89 °F, low 70 °F 89°70° JunJuly: average high 91 °F, low 74 °F 91°74° JulAugust: average high 90 °F, low 73 °F 90°73° AugSeptember: average high 85 °F, low 68 °F 85°68° SepOctober: average high 78 °F, low 58 °F 78°58° OctNovember: average high 69 °F, low 47 °F 69°47° NovDecember: average high 63 °F, low 42 °F 63°42° Dec

Precipitation by month inches

0″2″4″6″8″January: 3.37 in precipitation 3.4 JanFebruary: 3.33 in precipitation 3.3 FebMarch: 3.52 in precipitation 3.5 MarApril: 3.37 in precipitation 3.4 AprMay: 3.62 in precipitation 3.6 MayJune: 5.93 in precipitation 5.9 JunJuly: 6.82 in precipitation 6.8 JulAugust: 7.80 in precipitation 7.8 AugSeptember: 6.12 in precipitation 6.1 SepOctober: 3.97 in precipitation 4.0 OctNovember: 2.85 in precipitation 2.9 NovDecember: 3.63 in precipitation 3.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Charleston Intl Airport, SC (4 mi away); precipitation: North Charleston 2.9 Wnw, SC (within 1 mile). 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.

294189a
North Charleston, SC · 2 mi
294568b
Ladson, SC · 4 mi
294049a
Charleston Afb, SC · 4 mi
294069a
Charleston, SC · 4 mi
294109a
Hanahan, SC · 5 mi
294149a
Charleston, SC · 6 mi
294858b
Summerville, SC · 6 mi
294848b
Summerville, SC · 9 mi

All 5 ZIP codes in North Charleston → · South Carolina planting zones →

Questions about 29420

What planting zone is ZIP code 29420?

ZIP code 29420 (North Charleston, SC) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in North Charleston, SC?

The median last spring frost (32 °F) near 29420 is March 7; after March 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Charleston Intl Airport station.

When is the first frost in North Charleston, SC?

The median first fall frost near 29420 is November 27, giving a median frost-free growing season of 266 days.

When should I plant tomatoes in 29420?

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

How much rain and snow does 29420 get?

About 54.3 inches of precipitation a year (NOAA 1991–2020 normals, North Charleston 2.9 Wnw station).

How hot do summers get in North Charleston, SC?

The average high peaks at 91 °F in July, with about 64 days a year at 90 °F or more.

What kind of soil does 29420 have?

The USDA soil survey maps Wahee at the center of ZIP 29420: fine sandy loam, somewhat poorly drained, pH about 5.3 (strongly acidic).

Did spring come early in North Charleston, SC in 2026?

Spring leaf-out near 29420 came on Feb 3 in 2026, 3 days later than the 1991–2020 average (Jan 31), according to the USA National Phenology Network Spring Index.

What kind of onions grow in North Charleston, SC?

Intermediate onions: the longest day near 29420 is 14 h 20 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 29420 change?

Yes. The 2012 USDA map put 29420 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.