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

Planting zone for 45133 — Hillsboro, OH

ZIP code 45133 (Hillsboro, Highland County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 24 and the first fall frost October 20.

Where ZIP 45133 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 24
First frostOct 20
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 Hillsboro, 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 Hillsboro, OH

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 24median — 50% chance of a later frost
Safe for tender plantsMay 11only 10% chance of frost after
First fall frostOctober 20median — 10% chance by Oct 6
Growing season178 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 12 and returns around November 1.

From the NOAA station Hillsboro, OH — 6 miles away, elevation 955 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 45133

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 13 – Mar 27
SpinachSow outdoors · Mar 13 – Apr 3
Broccoli, cabbageStart indoors · Feb 13 – Feb 27
Broccoli, cabbageTransplant · Apr 3 – Apr 17
Onion setsPlant outdoors · Mar 27 – Apr 10
PotatoesPlant outdoors · Apr 3 – Apr 17
LettuceSow outdoors · Mar 27 – Apr 10
Carrots, beetsSow outdoors · Apr 3 – Apr 17
TomatoesStart indoors · Feb 27 – Mar 13
TomatoesTransplant · May 1 – May 15
Peppers, eggplantStart indoors · Feb 13 – Feb 27
Peppers, eggplantTransplant · May 8 – May 22
BeansSow outdoors · May 1 – May 15
Sweet cornSow outdoors · May 1 – May 15
Cucumbers, squashSow outdoors · May 1 – May 15
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 24) 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 45133 came on Mar 10 — 13 days earlier than the 1991–2020 average (Mar 23).

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.

Trees 71

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 203

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 vetch1.3 ft · blooms late spring · high shade tolerance · to −38 °F

Grasses 165

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 10

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Hillsboro, OH.

Soil in Hillsboro, OH

The soil mapped at the center of ZIP 45133 is Haubstadt — 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%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Haubstadt silt loam, 2 to 6 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 45133; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hillsboro, OH

Summer high85 °Faverage high, July
Winter low19 °Faverage low, January
Hot days10days a year at 90 °F or more
Freezing nights115nights a year at 32 °F or less
Growing degree days3,283base 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
Precipitation46.7 inper year, rain and melted snow
Snowfall18 inper year; 21 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 39 °F, low 19 °F 39°19° JanFebruary: average high 43 °F, low 22 °F 43°22° FebMarch: average high 53 °F, low 29 °F 53°29° MarApril: average high 65 °F, low 39 °F 65°39° AprMay: average high 74 °F, low 50 °F 74°50° MayJune: average high 82 °F, low 59 °F 82°59° JunJuly: average high 85 °F, low 62 °F 85°62° JulAugust: average high 83 °F, low 60 °F 83°60° AugSeptember: average high 78 °F, low 53 °F 78°53° SepOctober: average high 67 °F, low 42 °F 67°42° OctNovember: average high 54 °F, low 32 °F 54°32° NovDecember: average high 43 °F, low 25 °F 43°25° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.44 in precipitation, 6.9 in snowfall 3.4❄7 JanFebruary: 3.26 in precipitation, 5 in snowfall 3.3❄5 FebMarch: 4.20 in precipitation, 3.4 in snowfall 4.2❄3 MarApril: 4.85 in precipitation, 0.2 in snowfall 4.8 AprMay: 5.06 in precipitation 5.1 MayJune: 4.82 in precipitation 4.8 JunJuly: 4.25 in precipitation 4.3 JulAugust: 3.72 in precipitation 3.7 AugSeptember: 3.17 in precipitation 3.2 SepOctober: 3.19 in precipitation, 0.2 in snowfall 3.2 OctNovember: 3.10 in precipitation, 0.2 in snowfall 3.1 NovDecember: 3.62 in precipitation, 2.2 in snowfall 3.6❄2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hillsboro, OH (6 mi away); precipitation: Hillsboro, OH (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

451726b
Sinking Spring, OH · 12 mi
456246b
Cynthiana, OH · 12 mi
456796b
Seaman, OH · 13 mi
451556b
Mowrystown, OH · 13 mi
451326b
Highland, OH · 13 mi
451426b
Lynchburg, OH · 13 mi
451356b
Leesburg, OH · 13 mi
451596b
New Vienna, OH · 14 mi

Ohio planting zones →

Questions about 45133

What planting zone is ZIP code 45133?

ZIP code 45133 (Hillsboro, 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 Hillsboro, OH?

The median last spring frost (32 °F) near 45133 is April 24; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hillsboro station.

When is the first frost in Hillsboro, OH?

The median first fall frost near 45133 is October 20, giving a median frost-free growing season of 178 days.

When should I plant tomatoes in 45133?

Start tomato seeds indoors around Feb 27 – Mar 13 and set transplants outside around May 1 – May 15, one to three weeks after the median last frost.

How much rain and snow does 45133 get?

About 46.7 inches of precipitation a year and 18 inches of snowfall (NOAA 1991–2020 normals, Hillsboro station).

How hot do summers get in Hillsboro, OH?

The average high peaks at 85 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 45133 have?

The USDA soil survey maps Haubstadt at the center of ZIP 45133: silt loam, moderately well drained, pH about 5.9 (moderately acidic).

Did spring come early in Hillsboro, OH in 2026?

Spring leaf-out near 45133 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 Hillsboro, OH?

Intermediate onions: the longest day near 45133 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45133 change?

Yes. The 2012 USDA map put 45133 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.