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

Planting zone for 70549 — Lake Arthur, LA

ZIP code 70549 (Lake Arthur, Jefferson Davis County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 10 and the first fall frost December 11.

Where ZIP 70549 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 10

First frostDec 11

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 Lake Arthur, 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 Lake Arthur, LA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 10median — 50% chance of a later frost

Safe for tender plantsMarch 8only 10% chance of frost after

First fall frostDecember 11median — 10% chance by Nov 19

Growing season307 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 25 and returns around January 1.

From the NOAA station Lake Arthur 7 Sw, LA — 4 miles away, elevation 10 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 70549

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Dec 30 – Jan 13

SpinachSow outdoors · Dec 30 – Jan 20

Broccoli, cabbageStart indoors · Dec 2 – Dec 16

Broccoli, cabbageTransplant · Jan 20 – Feb 3

Onion setsPlant outdoors · Jan 13 – Jan 27

PotatoesPlant outdoors · Jan 20 – Feb 3

LettuceSow outdoors · Jan 13 – Jan 27

Carrots, beetsSow outdoors · Jan 20 – Feb 3

TomatoesStart indoors · Dec 16 – Dec 30

TomatoesTransplant · Feb 17 – Mar 3

Peppers, eggplantStart indoors · Dec 2 – Dec 16

Peppers, eggplantTransplant · Feb 24 – Mar 10

BeansSow outdoors · Feb 17 – Mar 3

Sweet cornSow outdoors · Feb 17 – Mar 3

Cucumbers, squashSow outdoors · Feb 17 – Mar 3

Fall lettuce, spinachSow outdoors · Oct 16 – Oct 30

GarlicPlant cloves · Nov 27 – Jan 1

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 10) and first fall frost (Dec 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 70549 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 Lake Arthur, LA.

Soil in Lake Arthur, LA

The soil mapped at the center of ZIP 70549 is Midland — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter2.25%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classprime farmlandUSDA classification

Map unit: Midland silty clay loam, 0 to 1 percent slopes, rarely 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 70549; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lake Arthur, LA

Summer high92 °Faverage high, August

Winter low44 °Faverage low, January

Hot days82days a year at 90 °F or more

Freezing nights10nights a year at 32 °F or less

Growing degree days7,182base 50 °F — the season’s usable heat

Longest day14 h 05 mindaylight on June 21

Shortest day10 h 12 mindaylight on December 21

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

Precipitation59.9 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: Lake Arthur 7 Sw, LA (4 mi away); precipitation: Lake Arthur 7 Sw, LA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Bell City, LA · 14 mi

706509a

Lacassine, LA · 14 mi

Louisiana planting zones →

Questions about 70549

What planting zone is ZIP code 70549?

ZIP code 70549 (Lake Arthur, 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 Lake Arthur, LA?

The median last spring frost (32 °F) near 70549 is February 10; after March 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lake Arthur 7 Sw station.

When is the first frost in Lake Arthur, LA?

The median first fall frost near 70549 is December 11, giving a median frost-free growing season of 307 days.

When should I plant tomatoes in 70549?

Start tomato seeds indoors around Dec 16 – Dec 30 and set transplants outside around Feb 17 – Mar 3, one to three weeks after the median last frost.

How much rain and snow does 70549 get?

About 59.9 inches of precipitation a year (NOAA 1991–2020 normals, Lake Arthur 7 Sw station).

How hot do summers get in Lake Arthur, LA?

The average high peaks at 92 °F in August, with about 82 days a year at 90 °F or more.

What kind of soil does 70549 have?

The USDA soil survey maps Midland at the center of ZIP 70549: silty clay loam, poorly drained, pH about 6.2 (slightly acidic).

Did spring come early in Lake Arthur, LA in 2026?

Spring leaf-out near 70549 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 Lake Arthur, LA?

Short-day onions: the longest day near 70549 is 14 h 05 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 70549 change?

Yes. The 2012 USDA map put 70549 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.