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

Planting zone for 70339 — Pierre Part, LA

ZIP code 70339 (Pierre Part, Assumption County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 21 and the first fall frost December 5.

Where ZIP 70339 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 21

First frostDec 5

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 Pierre Part, 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 Pierre Part, LA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostFebruary 21median — 50% chance of a later frost

Safe for tender plantsMarch 15only 10% chance of frost after

First fall frostDecember 5median — 10% chance by Nov 14

Growing season291 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 1 and returns around December 28.

From the NOAA station Donaldsonville 4 Sw, LA — 15 miles away, elevation 30 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 70339

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 10 – Jan 24

SpinachSow outdoors · Jan 10 – Jan 31

Broccoli, cabbageStart indoors · Dec 13 – Dec 27

Broccoli, cabbageTransplant · Jan 31 – Feb 14

Onion setsPlant outdoors · Jan 24 – Feb 7

PotatoesPlant outdoors · Jan 31 – Feb 14

LettuceSow outdoors · Jan 24 – Feb 7

Carrots, beetsSow outdoors · Jan 31 – Feb 14

TomatoesStart indoors · Dec 27 – Jan 10

TomatoesTransplant · Feb 28 – Mar 14

Peppers, eggplantStart indoors · Dec 13 – Dec 27

Peppers, eggplantTransplant · Mar 7 – Mar 21

BeansSow outdoors · Feb 28 – Mar 14

Sweet cornSow outdoors · Feb 28 – Mar 14

Cucumbers, squashSow outdoors · Feb 28 – Mar 14

Fall lettuce, spinachSow outdoors · Oct 10 – Oct 24

GarlicPlant cloves · Nov 21 – Dec 26

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 21) and first fall frost (Dec 5) 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 70339 came on Jan 11 — 13 days earlier than the 1991–2020 average (Jan 24).

average
Jan 242026
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 Pierre Part, LA.

Soil in Pierre Part, LA

The soil mapped at the center of ZIP 70339 is Thibaut — clay, poorly drained.

TextureClayholds water and nutrients; slow to drain and warm up

pH6.7neutral; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter2%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classprime farmlandUSDA classification

Map unit: Thibaut clay, 0 to 1 percent slopes.

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 70339; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Pierre Part, LA

Summer high91 °Faverage high, July

Winter low42 °Faverage low, January

Hot days80days a year at 90 °F or more

Freezing nights16nights a year at 32 °F or less

Growing degree days6,896base 50 °F — the season’s usable heat

Longest day14 h 04 mindaylight on June 21

Shortest day10 h 13 mindaylight on December 21

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

Precipitation63.3 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: Donaldsonville 4 Sw, LA (15 mi away); precipitation: Napoleonville, LA (11 mi away). 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.

703909b

Napoleonville, LA · 9 mi

703919a

Paincourtville, LA · 10 mi

703419a

Belle Rose, LA · 10 mi

703809b

Morgan City, LA · 12 mi

703939a

Plattenville, LA · 13 mi

703729b

Labadieville, LA · 14 mi

703429b

Berwick, LA · 15 mi

703819b

Morgan City, LA · 15 mi

Louisiana planting zones →

Questions about 70339

What planting zone is ZIP code 70339?

ZIP code 70339 (Pierre Part, 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 Pierre Part, LA?

The median last spring frost (32 °F) near 70339 is February 21; after March 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Donaldsonville 4 Sw station.

When is the first frost in Pierre Part, LA?

The median first fall frost near 70339 is December 5, giving a median frost-free growing season of 291 days.

When should I plant tomatoes in 70339?

Start tomato seeds indoors around Dec 27 – Jan 10 and set transplants outside around Feb 28 – Mar 14, one to three weeks after the median last frost.

How much rain and snow does 70339 get?

About 63.3 inches of precipitation a year (NOAA 1991–2020 normals, Napoleonville station).

How hot do summers get in Pierre Part, LA?

The average high peaks at 91 °F in July, with about 80 days a year at 90 °F or more.

What kind of soil does 70339 have?

The USDA soil survey maps Thibaut at the center of ZIP 70339: clay, poorly drained, pH about 6.7 (neutral).

Did spring come early in Pierre Part, LA in 2026?

Spring leaf-out near 70339 came on Jan 11 in 2026, 13 days earlier than the 1991–2020 average (Jan 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Pierre Part, LA?

Short-day onions: the longest day near 70339 is 14 h 04 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 70339 change?

Yes. The 2012 USDA map put 70339 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.