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

Planting zone for 42437 — Morganfield, KY

ZIP code 42437 (Morganfield, Union County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 5 and the first fall frost October 31.

Where ZIP 42437 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 5
First frostOct 31
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 Morganfield, 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 Morganfield, KY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 5median — 50% chance of a later frost
Safe for tender plantsApril 21only 10% chance of frost after
First fall frostOctober 31median — 10% chance by Oct 19
Growing season209 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 24 and returns around November 8.

From the NOAA station Jt Myers Locks & Dam, IN — 11 miles away, elevation 341 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 42437

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 22 – Mar 8
SpinachSow outdoors · Feb 22 – Mar 15
Broccoli, cabbageStart indoors · Jan 25 – Feb 8
Broccoli, cabbageTransplant · Mar 15 – Mar 29
Onion setsPlant outdoors · Mar 8 – Mar 22
PotatoesPlant outdoors · Mar 15 – Mar 29
LettuceSow outdoors · Mar 8 – Mar 22
Carrots, beetsSow outdoors · Mar 15 – Mar 29
TomatoesStart indoors · Feb 8 – Feb 22
TomatoesTransplant · Apr 12 – Apr 26
Peppers, eggplantStart indoors · Jan 25 – Feb 8
Peppers, eggplantTransplant · Apr 19 – May 3
BeansSow outdoors · Apr 12 – Apr 26
Sweet cornSow outdoors · Apr 12 – Apr 26
Cucumbers, squashSow outdoors · Apr 12 – Apr 26
Fall lettuce, spinachSow outdoors · Sep 5 – Sep 19
GarlicPlant cloves · Oct 17 – Nov 21
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 5) and first fall frost (Oct 31) 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 42437 came on Mar 2 — 6 days earlier than the 1991–2020 average (Mar 8).

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).

Soil in Morganfield, KY

The soil mapped at the center of ZIP 42437 is Steinsburg — loam, well drained.

TextureLoama good balance for most vegetables
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.75%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Steinsburg-Frondorf complex, 20 to 50 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 42437; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Morganfield, KY

Summer high88 °Faverage high, July
Winter low26 °Faverage low, January
Hot days44days a year at 90 °F or more
Freezing nights80nights a year at 32 °F or less
Growing degree days4,262base 50 °F — the season’s usable heat
Longest day14 h 46 mindaylight on June 21
Shortest day9 h 33 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation48.2 inper year, rain and melted snow
Snowfall8 inper year

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 42 °F, low 26 °F 42°26° JanFebruary: average high 47 °F, low 28 °F 47°28° FebMarch: average high 56 °F, low 37 °F 56°37° MarApril: average high 68 °F, low 46 °F 68°46° AprMay: average high 77 °F, low 56 °F 77°56° MayJune: average high 85 °F, low 64 °F 85°64° JunJuly: average high 88 °F, low 68 °F 88°68° JulAugust: average high 88 °F, low 66 °F 88°66° AugSeptember: average high 81 °F, low 59 °F 81°59° SepOctober: average high 70 °F, low 47 °F 70°47° OctNovember: average high 56 °F, low 36 °F 56°36° NovDecember: average high 45 °F, low 29 °F 45°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.57 in precipitation, 2.1 in snowfall 3.6❄2 JanFebruary: 3.50 in precipitation, 1.7 in snowfall 3.5❄2 FebMarch: 4.48 in precipitation, 0.7 in snowfall 4.5❄1 MarApril: 5.38 in precipitation 5.4 AprMay: 5.02 in precipitation 5.0 MayJune: 4.75 in precipitation 4.8 JunJuly: 3.65 in precipitation 3.6 JulAugust: 3.12 in precipitation 3.1 AugSeptember: 3.35 in precipitation 3.4 SepOctober: 3.28 in precipitation 3.3 OctNovember: 4.09 in precipitation 4.1 NovDecember: 4.02 in precipitation, 3 in snowfall 4.0❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Jt Myers Locks & Dam, IN (11 mi away); precipitation: Jt Myers Locks & Dam, IN (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

424597a
Sturgis, KY · 8 mi
424627a
Waverly, KY · 9 mi
424617a
Uniontown, KY · 10 mi
424607a
Sullivan, KY · 11 mi
424047a
Clay, KY · 12 mi
424637a
Wheatcroft, KY · 12 mi
424067a
Corydon, KY · 13 mi
424097a
Dixon, KY · 14 mi

Kentucky planting zones →

Questions about 42437

What planting zone is ZIP code 42437?

ZIP code 42437 (Morganfield, 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 Morganfield, KY?

The median last spring frost (32 °F) near 42437 is April 5; after April 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Jt Myers Locks & Dam station.

When is the first frost in Morganfield, KY?

The median first fall frost near 42437 is October 31, giving a median frost-free growing season of 209 days.

When should I plant tomatoes in 42437?

Start tomato seeds indoors around Feb 8 – Feb 22 and set transplants outside around Apr 12 – Apr 26, one to three weeks after the median last frost.

How much rain and snow does 42437 get?

About 48.2 inches of precipitation a year and 8 inches of snowfall (NOAA 1991–2020 normals, Jt Myers Locks & Dam station).

How hot do summers get in Morganfield, KY?

The average high peaks at 88 °F in July, with about 44 days a year at 90 °F or more.

What kind of soil does 42437 have?

The USDA soil survey maps Steinsburg at the center of ZIP 42437: loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Morganfield, KY in 2026?

Spring leaf-out near 42437 came on Mar 2 in 2026, 6 days earlier than the 1991–2020 average (Mar 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Morganfield, KY?

Intermediate onions: the longest day near 42437 is 14 h 46 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 42437 change?

Yes. The 2012 USDA map put 42437 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.