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

Planting zone for 70073 — Marrero, LA

ZIP code 70073 (Marrero, Jefferson Parish) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F.

Where ZIP 70073 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.

Zone9b25 to 30 °F

Coldest night−3.9 to −1.1 °C

Last frostrare

First frostrare

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 Marrero, 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

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station New Orleans Audubon, LA — 2 miles away, elevation 20 ft) the median growing season is 341 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 70073 came on Jan 11 — 12 days earlier than the 1991–2020 average (Jan 23).

average
Jan 232026
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 Marrero, LA.

Soil in Marrero, LA

The soil mapped at the center of ZIP 70073 is Cancienne — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH5.7moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.25%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Cancienne silt loam, 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 70073; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Marrero, LA

Summer high94 °Faverage high, July

Winter low47 °Faverage low, January

Hot days106days a year at 90 °F or more

Freezing nights4nights a year at 32 °F or less

Growing degree days8,076base 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

Precipitation64.6 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: New Orleans Audubon, LA (2 mi away); precipitation: New Orleans Audubon, LA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

700599b

Harvey, LA · 1 mi

701159b

New Orleans, LA · 2 mi

701589b

New Orleans, LA · 2 mi

New Orleans, LA · 3 mi

700539b

Gretna, LA · 3 mi

All 2 ZIP codes in Marrero → · Louisiana planting zones →

Questions about 70073

What planting zone is ZIP code 70073?

ZIP code 70073 (Marrero, 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).

How much rain and snow does 70073 get?

About 64.6 inches of precipitation a year (NOAA 1991–2020 normals, New Orleans Audubon station).

How hot do summers get in Marrero, LA?

The average high peaks at 94 °F in July, with about 106 days a year at 90 °F or more.

What kind of soil does 70073 have?

The USDA soil survey maps Cancienne at the center of ZIP 70073: silt loam, somewhat poorly drained, pH about 5.7 (moderately acidic).

Did spring come early in Marrero, LA in 2026?

Spring leaf-out near 70073 came on Jan 11 in 2026, 12 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Marrero, LA?

Short-day onions: the longest day near 70073 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 70073 change?

Yes. The 2012 USDA map put 70073 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.