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

Planting zone for 29938 — Hilton Head Island, SC

ZIP code 29938 (Hilton Head Island, Beaufort County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is March 3 and the first fall frost December 9.

Where ZIP 29938 is

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 3

First frostDec 9

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 Hilton Head Island, 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 Hilton Head Island, SC

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 3median — 50% chance of a later frost

Safe for tender plantsMarch 20only 10% chance of frost after

First fall frostDecember 9median — 10% chance by Nov 21

Growing season282 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 9 and returns around December 28.

From the NOAA station Beaufort Wwtp, SC — 2 miles away, elevation 26 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 29938

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 20 – Feb 3

SpinachSow outdoors · Jan 20 – Feb 10

Broccoli, cabbageStart indoors · Dec 23 – Jan 6

Broccoli, cabbageTransplant · Feb 10 – Feb 24

Onion setsPlant outdoors · Feb 3 – Feb 17

PotatoesPlant outdoors · Feb 10 – Feb 24

LettuceSow outdoors · Feb 3 – Feb 17

Carrots, beetsSow outdoors · Feb 10 – Feb 24

TomatoesStart indoors · Jan 6 – Jan 20

TomatoesTransplant · Mar 10 – Mar 24

Peppers, eggplantStart indoors · Dec 23 – Jan 6

Peppers, eggplantTransplant · Mar 17 – Mar 31

BeansSow outdoors · Mar 10 – Mar 24

Sweet cornSow outdoors · Mar 10 – Mar 24

Cucumbers, squashSow outdoors · Mar 10 – Mar 24

Fall lettuce, spinachSow outdoors · Oct 14 – Oct 28

GarlicPlant cloves · Nov 25 – Dec 30

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 3) and first fall frost (Dec 9) 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 29938 came on Feb 5 — 8 days later than the 1991–2020 average (Jan 28).

average
Jan 282026
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 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.

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 Hilton Head Island, SC.

Soil in Hilton Head Island, SC

The soil mapped at the center of ZIP 29938 is Bladen — fine sandy loam, poorly drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH4.6strongly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter2%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Bladen 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 29938; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hilton Head Island, SC

Summer high91 °Faverage high, July

Winter low41 °Faverage low, January

Hot days58days a year at 90 °F or more

Freezing nights13nights a year at 32 °F or less

Growing degree days6,719base 50 °F — the season’s usable heat

Longest day14 h 17 mindaylight on June 21

Shortest day10 h 01 mindaylight on December 21

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

Precipitation45 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: Beaufort Wwtp, SC (2 mi away); precipitation: Beaufort Mcas, SC (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

299359a

Port Royal, SC · 2 mi

299059a

Parris Island, SC · 3 mi

Saint Helena Island, SC · 7 mi

All 4 ZIP codes in Hilton Head Island → · South Carolina planting zones →

Questions about 29938

What planting zone is ZIP code 29938?

ZIP code 29938 (Hilton Head Island, 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 Hilton Head Island, SC?

The median last spring frost (32 °F) near 29938 is March 3; after March 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Beaufort Wwtp station.

When is the first frost in Hilton Head Island, SC?

The median first fall frost near 29938 is December 9, giving a median frost-free growing season of 282 days.

When should I plant tomatoes in 29938?

Start tomato seeds indoors around Jan 6 – Jan 20 and set transplants outside around Mar 10 – Mar 24, one to three weeks after the median last frost.

How much rain and snow does 29938 get?

About 45 inches of precipitation a year (NOAA 1991–2020 normals, Beaufort Mcas station).

How hot do summers get in Hilton Head Island, SC?

The average high peaks at 91 °F in July, with about 58 days a year at 90 °F or more.

What kind of soil does 29938 have?

The USDA soil survey maps Bladen at the center of ZIP 29938: fine sandy loam, poorly drained, pH about 4.6 (strongly acidic).

Did spring come early in Hilton Head Island, SC in 2026?

Spring leaf-out near 29938 came on Feb 5 in 2026, 8 days later than the 1991–2020 average (Jan 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hilton Head Island, SC?

Short-day onions: the longest day near 29938 is 14 h 17 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 29938 change?

Yes. The 2012 USDA map put 29938 in zone 8b; the 2023 map puts it in zone 9a. The newer map uses 1991–2020 data and more weather stations.