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

Planting zone for 42157 — Mount Hermon, KY

ZIP code 42157 (Mount Hermon, Monroe County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 26 and the first fall frost October 18.

Where ZIP 42157 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 26
First frostOct 18
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 Mount Hermon, 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 Mount Hermon, KY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 26median — 50% chance of a later frost
Safe for tender plantsMay 16only 10% chance of frost after
First fall frostOctober 18median — 10% chance by Oct 5
Growing season174 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 12 and returns around October 27.

From the NOAA station Summer Shade, KY — 9 miles away, elevation 863 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 42157

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 15 – Mar 29
SpinachSow outdoors · Mar 15 – Apr 5
Broccoli, cabbageStart indoors · Feb 15 – Mar 1
Broccoli, cabbageTransplant · Apr 5 – Apr 19
Onion setsPlant outdoors · Mar 29 – Apr 12
PotatoesPlant outdoors · Apr 5 – Apr 19
LettuceSow outdoors · Mar 29 – Apr 12
Carrots, beetsSow outdoors · Apr 5 – Apr 19
TomatoesStart indoors · Mar 1 – Mar 15
TomatoesTransplant · May 3 – May 17
Peppers, eggplantStart indoors · Feb 15 – Mar 1
Peppers, eggplantTransplant · May 10 – May 24
BeansSow outdoors · May 3 – May 17
Sweet cornSow outdoors · May 3 – May 17
Cucumbers, squashSow outdoors · May 3 – May 17
Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6
GarlicPlant cloves · Oct 4 – Nov 8
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 26) and first fall frost (Oct 18) 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 42157 came on Mar 1 — about the same time as the 1991–2020 average (Feb 28).

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.

Trees 78

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 109

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 181

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 153

autumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fblister sedge3 ft · blooms late spring · medium shade tolerance · to −38 °Fbluejoint5 ft · blooms late spring · high shade tolerance · to −33 °F

Vines 14

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °F

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 Mount Hermon, KY.

Soil in Mount Hermon, KY

The soil mapped at the center of ZIP 42157 is Waynesboro — loam, well drained.

TextureLoama good balance for most vegetables
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Waynesboro loam, 12 to 20 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 42157; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mount Hermon, KY

Summer high90 °Faverage high, July
Winter low24 °Faverage low, January
Hot days34days a year at 90 °F or more
Freezing nights101nights a year at 32 °F or less
Growing degree days4,103base 50 °F — the season’s usable heat
Longest day14 h 41 mindaylight on June 21
Shortest day9 h 38 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation54.4 inper year, rain and melted snow
Snowfall6 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 48 °F, low 24 °F 48°24° JanFebruary: average high 53 °F, low 27 °F 53°27° FebMarch: average high 61 °F, low 34 °F 61°34° MarApril: average high 72 °F, low 43 °F 72°43° AprMay: average high 80 °F, low 52 °F 80°52° MayJune: average high 86 °F, low 59 °F 86°59° JunJuly: average high 90 °F, low 63 °F 90°63° JulAugust: average high 89 °F, low 61 °F 89°61° AugSeptember: average high 82 °F, low 55 °F 82°55° SepOctober: average high 73 °F, low 44 °F 73°44° OctNovember: average high 61 °F, low 33 °F 61°33° NovDecember: average high 51 °F, low 27 °F 51°27° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 4.47 in precipitation, 1.9 in snowfall 4.5❄2 JanFebruary: 4.42 in precipitation, 1.8 in snowfall 4.4❄2 FebMarch: 5.20 in precipitation, 1 in snowfall 5.2❄1 MarApril: 4.97 in precipitation 5.0 AprMay: 5.37 in precipitation 5.4 MayJune: 4.89 in precipitation 4.9 JunJuly: 5.32 in precipitation 5.3 JulAugust: 3.66 in precipitation 3.7 AugSeptember: 3.79 in precipitation 3.8 SepOctober: 3.69 in precipitation 3.7 OctNovember: 3.92 in precipitation 3.9 NovDecember: 4.67 in precipitation, 1 in snowfall 4.7❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Summer Shade, KY (9 mi away); precipitation: Tompkinsville 9nw, KY (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

421317a
Etoile, KY · 6 mi
421667a
Summer Shade, KY · 8 mi
421337a
Fountain Run, KY · 8 mi
421407a
Gamaliel, KY · 9 mi
421677a
Tompkinsville, KY · 9 mi
421307a
Eighty Eight, KY · 10 mi
421237a
Austin, KY · 10 mi
421247a
Beaumont, KY · 11 mi

Kentucky planting zones →

Questions about 42157

What planting zone is ZIP code 42157?

ZIP code 42157 (Mount Hermon, 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 Mount Hermon, KY?

The median last spring frost (32 °F) near 42157 is April 26; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Summer Shade station.

When is the first frost in Mount Hermon, KY?

The median first fall frost near 42157 is October 18, giving a median frost-free growing season of 174 days.

When should I plant tomatoes in 42157?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 42157 get?

About 54.4 inches of precipitation a year and 6 inches of snowfall (NOAA 1991–2020 normals, Tompkinsville 9nw station).

How hot do summers get in Mount Hermon, KY?

The average high peaks at 90 °F in July, with about 34 days a year at 90 °F or more.

What kind of soil does 42157 have?

The USDA soil survey maps Waynesboro at the center of ZIP 42157: loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Mount Hermon, KY in 2026?

Spring leaf-out near 42157 came on Mar 1 in 2026, about the same as the 1991–2020 average (Feb 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mount Hermon, KY?

Intermediate onions: the longest day near 42157 is 14 h 41 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 42157 change?

Yes. The 2012 USDA map put 42157 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.