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

Planting zone for 42219 — Dunbar, KY

ZIP code 42219 (Dunbar, Butler County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 15 and the first fall frost October 20.

Where ZIP 42219 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 15
First frostOct 20
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 Dunbar, 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 Dunbar, KY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 15median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 20median — 10% chance by Oct 9
Growing season187 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 2 and returns around October 30.

From the NOAA station Rochester Ferry, KY — 7 miles away, elevation 390 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 42219

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 4 – Mar 18
SpinachSow outdoors · Mar 4 – Mar 25
Broccoli, cabbageStart indoors · Feb 4 – Feb 18
Broccoli, cabbageTransplant · Mar 25 – Apr 8
Onion setsPlant outdoors · Mar 18 – Apr 1
PotatoesPlant outdoors · Mar 25 – Apr 8
LettuceSow outdoors · Mar 18 – Apr 1
Carrots, beetsSow outdoors · Mar 25 – Apr 8
TomatoesStart indoors · Feb 18 – Mar 4
TomatoesTransplant · Apr 22 – May 6
Peppers, eggplantStart indoors · Feb 4 – Feb 18
Peppers, eggplantTransplant · Apr 29 – May 13
BeansSow outdoors · Apr 22 – May 6
Sweet cornSow outdoors · Apr 22 – May 6
Cucumbers, squashSow outdoors · Apr 22 – May 6
Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8
GarlicPlant cloves · Oct 6 – Nov 10
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 15) and first fall frost (Oct 20) 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 42219 came on Mar 1 — 5 days earlier than the 1991–2020 average (Mar 6).

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 Dunbar, KY

The soil mapped at the center of ZIP 42219 is Otwell — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH5.9moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Otwell silt loam, 2 to 6 percent slopes, occasionally 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 42219; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dunbar, KY

Summer high89 °Faverage high, July
Winter low24 °Faverage low, January
Hot days47days a year at 90 °F or more
Freezing nights97nights a year at 32 °F or less
Growing degree days4,018base 50 °F — the season’s usable heat
Longest day14 h 43 mindaylight on June 21
Shortest day9 h 36 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation54.9 inper year, rain and melted snow
Snowfall7 inper year; 1 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 44 °F, low 24 °F 44°24° JanFebruary: average high 48 °F, low 26 °F 48°26° FebMarch: average high 58 °F, low 34 °F 58°34° MarApril: average high 69 °F, low 43 °F 69°43° AprMay: average high 78 °F, low 53 °F 78°53° MayJune: average high 86 °F, low 61 °F 86°61° JunJuly: average high 89 °F, low 65 °F 89°65° JulAugust: average high 88 °F, low 63 °F 88°63° AugSeptember: average high 82 °F, low 56 °F 82°56° SepOctober: average high 71 °F, low 43 °F 71°43° OctNovember: average high 58 °F, low 34 °F 58°34° NovDecember: average high 48 °F, low 27 °F 48°27° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 4.13 in precipitation, 2.1 in snowfall 4.1❄2 JanFebruary: 4.56 in precipitation, 3.2 in snowfall 4.6❄3 FebMarch: 5.20 in precipitation, 1.6 in snowfall 5.2❄2 MarApril: 5.16 in precipitation 5.2 AprMay: 5.38 in precipitation 5.4 MayJune: 5.14 in precipitation 5.1 JunJuly: 4.56 in precipitation 4.6 JulAugust: 3.71 in precipitation 3.7 AugSeptember: 3.86 in precipitation 3.9 SepOctober: 4.25 in precipitation 4.3 OctNovember: 3.94 in precipitation, 0.1 in snowfall 3.9 NovDecember: 5.01 in precipitation, 0.3 in snowfall 5.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rochester Ferry, KY (7 mi away); precipitation: Aberdeen, KY (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

422737a
Rochester, KY · 6 mi
422617a
Morgantown, KY · 7 mi
422887a
Woodbury, KY · 7 mi
422017a
Aberdeen, KY · 7 mi
423377a
Drakesboro, KY · 10 mi
423397a
Dunmor, KY · 11 mi
423207a
Beaver Dam, KY · 12 mi
423247a
Belton, KY · 14 mi

Kentucky planting zones →

Questions about 42219

What planting zone is ZIP code 42219?

ZIP code 42219 (Dunbar, 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 Dunbar, KY?

The median last spring frost (32 °F) near 42219 is April 15; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rochester Ferry station.

When is the first frost in Dunbar, KY?

The median first fall frost near 42219 is October 20, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 42219?

Start tomato seeds indoors around Feb 18 – Mar 4 and set transplants outside around Apr 22 – May 6, one to three weeks after the median last frost.

How much rain and snow does 42219 get?

About 54.9 inches of precipitation a year and 7 inches of snowfall (NOAA 1991–2020 normals, Aberdeen station).

How hot do summers get in Dunbar, KY?

The average high peaks at 89 °F in July, with about 47 days a year at 90 °F or more.

What kind of soil does 42219 have?

The USDA soil survey maps Otwell at the center of ZIP 42219: silt loam, moderately well drained, pH about 5.9 (moderately acidic).

Did spring come early in Dunbar, KY in 2026?

Spring leaf-out near 42219 came on Mar 1 in 2026, 5 days earlier than the 1991–2020 average (Mar 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dunbar, KY?

Intermediate onions: the longest day near 42219 is 14 h 43 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 42219 change?

Yes. The 2012 USDA map put 42219 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.