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

Planting zone for 70358 — Grand Isle, LA

ZIP code 70358 (Grand Isle, Jefferson Parish) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F. The median last spring frost is February 8 and the first fall frost December 19.

Where ZIP 70358 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.

Zone10a30 to 35 °F

Coldest night−1.1 to 1.7 °C

Last frostFeb 8

First frostDec 19

2012 zone9b

Was 9b 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 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Grand Isle, LA…

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 Grand Isle, LA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 8median — 50% chance of a later frost

Safe for tender plantsMarch 12only 10% chance of frost after

First fall frostDecember 19median — 10% chance by Nov 20

Growing season311 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 28 and returns around January 3.

From the NOAA station Galliano, LA — 24 miles away, elevation 7 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 70358

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Dec 28 – Jan 11

SpinachSow outdoors · Dec 28 – Jan 18

Broccoli, cabbageStart indoors · Nov 30 – Dec 14

Broccoli, cabbageTransplant · Jan 18 – Feb 1

Onion setsPlant outdoors · Jan 11 – Jan 25

PotatoesPlant outdoors · Jan 18 – Feb 1

LettuceSow outdoors · Jan 11 – Jan 25

Carrots, beetsSow outdoors · Jan 18 – Feb 1

TomatoesStart indoors · Dec 14 – Dec 28

TomatoesTransplant · Feb 15 – Mar 1

Peppers, eggplantStart indoors · Nov 30 – Dec 14

Peppers, eggplantTransplant · Feb 22 – Mar 8

BeansSow outdoors · Feb 15 – Mar 1

Sweet cornSow outdoors · Feb 15 – Mar 1

Cucumbers, squashSow outdoors · Feb 15 – Mar 1

Fall lettuce, spinachSow outdoors · Oct 24 – Nov 7

GarlicPlant cloves · Dec 5 – Jan 9

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 8) and first fall frost (Dec 19) 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 70358 came on Jan 11 — 10 days earlier than the 1991–2020 average (Jan 21).

average
Jan 212026
Jan 11

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 10a in Louisiana

520 plants native to the lower 48 states, recorded in Louisiana, and rated by the USDA to survive 30 °F or colder — the bottom of zone 10a. 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 Grand Isle, LA.

Soil in Grand Isle, LA

The soil mapped at the center of ZIP 70358 is Scatlake — muck, very poorly drained.

TextureMucktop layer

pH6.0slightly acidic; most vegetables like 6.0–7.0

DrainageVery poorly drainedconsider raised beds

Organic matter50%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Scatlake muck, 0 to 0.2 percent slopes, tidal.

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 70358; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Grand Isle, LA

Summer high89 °Faverage high, July

Winter low45 °Faverage low, January

Hot days49days a year at 90 °F or more

Freezing nights9nights a year at 32 °F or less

Growing degree days7,261base 50 °F — the season’s usable heat

Longest day14 h 01 mindaylight on June 21

Shortest day10 h 16 mindaylight on December 21

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

Precipitation62.4 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: Galliano, LA (24 mi away); precipitation: Grand Isle, LA (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

7035710a

Golden Meadow, LA · 10 mi

700839b

Port Sulphur, LA · 23 mi

Pointe A La Hache, LA · 30 mi

703739b

Larose, LA · 31 mi

701819b

New Orleans, LA · 32 mi

Louisiana planting zones →

Questions about 70358

What planting zone is ZIP code 70358?

ZIP code 70358 (Grand Isle, LA) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

When is the last frost in Grand Isle, LA?

The median last spring frost (32 °F) near 70358 is February 8; after March 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Galliano station.

When is the first frost in Grand Isle, LA?

The median first fall frost near 70358 is December 19, giving a median frost-free growing season of 311 days.

When should I plant tomatoes in 70358?

Start tomato seeds indoors around Dec 14 – Dec 28 and set transplants outside around Feb 15 – Mar 1, one to three weeks after the median last frost.

How much rain and snow does 70358 get?

About 62.4 inches of precipitation a year (NOAA 1991–2020 normals, Grand Isle station).

How hot do summers get in Grand Isle, LA?

The average high peaks at 89 °F in July, with about 49 days a year at 90 °F or more.

What kind of soil does 70358 have?

The USDA soil survey maps Scatlake at the center of ZIP 70358: muck, very poorly drained, pH about 6.0 (slightly acidic).

Did spring come early in Grand Isle, LA in 2026?

Spring leaf-out near 70358 came on Jan 11 in 2026, 10 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Grand Isle, LA?

Short-day onions: the longest day near 70358 is 14 h 01 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 70358 change?

Yes. The 2012 USDA map put 70358 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.