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

Planting zone for 70643 — Grand Chenier, LA

ZIP code 70643 (Grand Chenier, Cameron County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 2 and the first fall frost December 23.

Where ZIP 70643 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.

Zone9b25 to 30 °F

Coldest night−3.9 to −1.1 °C

Last frostFeb 2

First frostDec 23

2012 zone9a

Was 9a 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 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Grand Chenier, 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 Chenier, LA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 2median — 50% chance of a later frost

Safe for tender plantsMarch 4only 10% chance of frost after

First fall frostDecember 23median — 10% chance by Nov 29

Growing season323 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 21 and returns around January 5.

From the NOAA station Rockefeller Wl Refuge, LA — 2 miles away, elevation 3 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 70643

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Dec 22 – Jan 5

SpinachSow outdoors · Dec 22 – Jan 12

Broccoli, cabbageStart indoors · Nov 24 – Dec 8

Broccoli, cabbageTransplant · Jan 12 – Jan 26

Onion setsPlant outdoors · Jan 5 – Jan 19

PotatoesPlant outdoors · Jan 12 – Jan 26

LettuceSow outdoors · Jan 5 – Jan 19

Carrots, beetsSow outdoors · Jan 12 – Jan 26

TomatoesStart indoors · Dec 8 – Dec 22

TomatoesTransplant · Feb 9 – Feb 23

Peppers, eggplantStart indoors · Nov 24 – Dec 8

Peppers, eggplantTransplant · Feb 16 – Mar 2

BeansSow outdoors · Feb 9 – Feb 23

Sweet cornSow outdoors · Feb 9 – Feb 23

Cucumbers, squashSow outdoors · Feb 9 – Feb 23

Fall lettuce, spinachSow outdoors · Oct 28 – Nov 11

GarlicPlant cloves · Dec 9 – Jan 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 2) and first fall frost (Dec 23) 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 70643 came on Jan 11 — 14 days earlier than the 1991–2020 average (Jan 25).

average
Jan 252026
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 9b in Louisiana

519 plants native to the lower 48 states, recorded in Louisiana, and rated by the USDA to survive 25 °F or colder — the bottom of zone 9b. 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 Chenier, LA.

Soil in Grand Chenier, LA

The soil mapped at the center of ZIP 70643 is Clovelly — muck, very poorly drained.

TextureMucktop layer

pH6.6neutral; most vegetables like 6.0–7.0

DrainageVery poorly drainedconsider raised beds

Organic matter45.5%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classNot prime farmlandUSDA classification

Map unit: Clovelly muck, 0 to 0.2 percent slopes, very frequently flooded.

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 70643; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Grand Chenier, LA

Summer high91 °Faverage high, August

Winter low45 °Faverage low, January

Hot days60days a year at 90 °F or more

Freezing nights8nights a year at 32 °F or less

Growing degree days7,346base 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

Precipitation59.4 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: Rockefeller Wl Refuge, LA (2 mi away); precipitation: Rockefeller Wl Refuge, LA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

706329b

Creole, LA · 12 mi

705499b

Lake Arthur, LA · 22 mi

Bell City, LA · 26 mi

Lake Charles, LA · 32 mi

Louisiana planting zones →

Questions about 70643

What planting zone is ZIP code 70643?

ZIP code 70643 (Grand Chenier, LA) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Grand Chenier, LA?

The median last spring frost (32 °F) near 70643 is February 2; after March 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rockefeller Wl Refuge station.

When is the first frost in Grand Chenier, LA?

The median first fall frost near 70643 is December 23, giving a median frost-free growing season of 323 days.

When should I plant tomatoes in 70643?

Start tomato seeds indoors around Dec 8 – Dec 22 and set transplants outside around Feb 9 – Feb 23, one to three weeks after the median last frost.

How much rain and snow does 70643 get?

About 59.4 inches of precipitation a year (NOAA 1991–2020 normals, Rockefeller Wl Refuge station).

How hot do summers get in Grand Chenier, LA?

The average high peaks at 91 °F in August, with about 60 days a year at 90 °F or more.

What kind of soil does 70643 have?

The USDA soil survey maps Clovelly at the center of ZIP 70643: muck, very poorly drained, pH about 6.6 (neutral).

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

Spring leaf-out near 70643 came on Jan 11 in 2026, 14 days earlier than the 1991–2020 average (Jan 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Grand Chenier, LA?

Short-day onions: the longest day near 70643 is 14 h 03 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 70643 change?

Yes. The 2012 USDA map put 70643 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.