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

Planting zone for 40223 — Louisville, KY

ZIP code 40223 (Louisville, Jefferson County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 3 and the first fall frost November 3.

Where ZIP 40223 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostApr 3

First frostNov 3

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Louisville, KY…

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 Louisville, KY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 3median — 50% chance of a later frost

Safe for tender plantsApril 19only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 21

Growing season214 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 22 and returns around November 13.

From the NOAA station Louisville Bowman Field, KY — 7 miles away, elevation 541 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 40223

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 20 – Mar 6

SpinachSow outdoors · Feb 20 – Mar 13

Broccoli, cabbageStart indoors · Jan 23 – Feb 6

Broccoli, cabbageTransplant · Mar 13 – Mar 27

Onion setsPlant outdoors · Mar 6 – Mar 20

PotatoesPlant outdoors · Mar 13 – Mar 27

LettuceSow outdoors · Mar 6 – Mar 20

Carrots, beetsSow outdoors · Mar 13 – Mar 27

TomatoesStart indoors · Feb 6 – Feb 20

TomatoesTransplant · Apr 10 – Apr 24

Peppers, eggplantStart indoors · Jan 23 – Feb 6

Peppers, eggplantTransplant · Apr 17 – May 1

BeansSow outdoors · Apr 10 – Apr 24

Sweet cornSow outdoors · Apr 10 – Apr 24

Cucumbers, squashSow outdoors · Apr 10 – Apr 24

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 3) and first fall frost (Nov 3) 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 40223 came on Mar 3 — 8 days earlier than the 1991–2020 average (Mar 11).

average
Mar 112026
Mar 3

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 7a in Kentucky

547 plants native to the lower 48 states, recorded in Kentucky, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Louisville, KY.

Soil in Louisville, KY

The soil mapped at the center of ZIP 40223 is Crider — silt loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSilt loama good balance for most vegetables

pH5.6moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Alfic Udarents-Crider complex, 0 to 12 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 40223; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Louisville, KY

Summer high88 °Faverage high, July

Winter low27 °Faverage low, January

Hot days38days a year at 90 °F or more

Freezing nights80nights a year at 32 °F or less

Growing degree days4,455base 50 °F — the season’s usable heat

Longest day14 h 50 mindaylight on June 21

Shortest day9 h 30 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation48 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: Louisville Bowman Field, KY (7 mi away); precipitation: Lyndon 1.1 E, KY (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

402437a

Louisville, KY · 1 mi

402427a

Louisville, KY · 3 mi

402417a

Louisville, KY · 3 mi

402227a

Louisville, KY · 4 mi

400566b

Pewee Valley, KY · 4 mi

400187a

Eastwood, KY · 5 mi

402457a

Louisville, KY · 5 mi

402207a

Louisville, KY · 5 mi

All 65 ZIP codes in Louisville → · Kentucky planting zones →

Questions about 40223

What planting zone is ZIP code 40223?

ZIP code 40223 (Louisville, KY) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Louisville, KY?

The median last spring frost (32 °F) near 40223 is April 3; after April 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Louisville Bowman Field station.

When is the first frost in Louisville, KY?

The median first fall frost near 40223 is November 3, giving a median frost-free growing season of 214 days.

When should I plant tomatoes in 40223?

Start tomato seeds indoors around Feb 6 – Feb 20 and set transplants outside around Apr 10 – Apr 24, one to three weeks after the median last frost.

How much rain and snow does 40223 get?

About 48 inches of precipitation a year (NOAA 1991–2020 normals, Lyndon 1.1 E station).

How hot do summers get in Louisville, KY?

The average high peaks at 88 °F in July, with about 38 days a year at 90 °F or more.

What kind of soil does 40223 have?

The USDA soil survey maps Crider at the center of ZIP 40223: silt loam, well drained, pH about 5.6 (moderately acidic).

Did spring come early in Louisville, KY in 2026?

Spring leaf-out near 40223 came on Mar 3 in 2026, 8 days earlier than the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Louisville, KY?

Intermediate onions: the longest day near 40223 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 40223 change?

Yes. The 2012 USDA map put 40223 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.