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

Planting zone for 45154 — Mount Orab, OH

ZIP code 45154 (Mount Orab, Brown County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 29 and the first fall frost October 11.

Where ZIP 45154 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostApr 29

First frostOct 11

2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mount Orab, OH…

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 Orab, OH

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 29median — 50% chance of a later frost

Safe for tender plantsMay 16only 10% chance of frost after

First fall frostOctober 11median — 10% chance by Sep 28

Growing season162 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 20 and returns around October 21.

From the NOAA station Ripley Exp Farm, OH — 20 miles away, elevation 879 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 45154

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 18 – Apr 1

SpinachSow outdoors · Mar 18 – Apr 8

Broccoli, cabbageStart indoors · Feb 18 – Mar 4

Broccoli, cabbageTransplant · Apr 8 – Apr 22

Onion setsPlant outdoors · Apr 1 – Apr 15

PotatoesPlant outdoors · Apr 8 – Apr 22

LettuceSow outdoors · Apr 1 – Apr 15

Carrots, beetsSow outdoors · Apr 8 – Apr 22

TomatoesStart indoors · Mar 4 – Mar 18

TomatoesTransplant · May 6 – May 20

Peppers, eggplantStart indoors · Feb 18 – Mar 4

Peppers, eggplantTransplant · May 13 – May 27

BeansSow outdoors · May 6 – May 20

Sweet cornSow outdoors · May 6 – May 20

Cucumbers, squashSow outdoors · May 6 – May 20

Fall lettuce, spinachSow outdoors · Aug 16 – Aug 30

GarlicPlant cloves · Sep 27 – Nov 1

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 11) 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 45154 came on Mar 10 — 13 days earlier than the 1991–2020 average (Mar 23).

average
Mar 232026
Mar 10

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 6b in Ohio

570 plants native to the lower 48 states, recorded in Ohio, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Mount Orab, OH.

Soil in Mount Orab, OH

The soil mapped at the center of ZIP 45154 is Westboro — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH5.5moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.1%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Westboro-Schaffer silt loams, 0 to 2 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 45154; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mount Orab, OH

Summer high86 °Faverage high, July

Winter low17 °Faverage low, January

Hot days21days a year at 90 °F or more

Freezing nights128nights a year at 32 °F or less

Growing degree days3,172base 50 °F — the season’s usable heat

Longest day14 h 55 mindaylight on June 21

Shortest day9 h 25 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

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ripley Exp Farm, OH (20 mi away); precipitation: Fayetteville 0.5 W, OH (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

451766b

Williamsburg, OH · 6 mi

451716b

Sardinia, OH · 7 mi

451186b

Fayetteville, OH · 8 mi

451556b

Mowrystown, OH · 9 mi

451066b

Bethel, OH · 11 mi

451306b

Hamersville, OH · 12 mi

451426b

Lynchburg, OH · 12 mi

451586b

Newtonsville, OH · 12 mi

Ohio planting zones →

Questions about 45154

What planting zone is ZIP code 45154?

ZIP code 45154 (Mount Orab, OH) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Mount Orab, OH?

The median last spring frost (32 °F) near 45154 is April 29; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ripley Exp Farm station.

When is the first frost in Mount Orab, OH?

The median first fall frost near 45154 is October 11, giving a median frost-free growing season of 162 days.

When should I plant tomatoes in 45154?

Start tomato seeds indoors around Mar 4 – Mar 18 and set transplants outside around May 6 – May 20, one to three weeks after the median last frost.

How much rain and snow does 45154 get?

About 48.2 inches of precipitation a year (NOAA 1991–2020 normals, Fayetteville 0.5 W station).

How hot do summers get in Mount Orab, OH?

The average high peaks at 86 °F in July, with about 21 days a year at 90 °F or more.

What kind of soil does 45154 have?

The USDA soil survey maps Westboro at the center of ZIP 45154: silt loam, somewhat poorly drained, pH about 5.5 (moderately acidic).

Did spring come early in Mount Orab, OH in 2026?

Spring leaf-out near 45154 came on Mar 10 in 2026, 13 days earlier than the 1991–2020 average (Mar 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mount Orab, OH?

Intermediate onions: the longest day near 45154 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45154 change?

Yes. The 2012 USDA map put 45154 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.