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

Planting zone for 45233 — Cincinnati, OH

ZIP code 45233 (Cincinnati, Hamilton County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 13 and the first fall frost October 31.

Where ZIP 45233 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 13
First frostOct 31
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 Cincinnati, 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 Cincinnati, OH

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 13median — 50% chance of a later frost
Safe for tender plantsMay 2only 10% chance of frost after
First fall frostOctober 31median — 10% chance by Oct 17
Growing season197 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 31 and returns around November 10.

From the NOAA station Cincinnati-Fernbank, OH — within 1 mile, elevation 499 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 45233

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 2 – Mar 16
SpinachSow outdoors · Mar 2 – Mar 23
Broccoli, cabbageStart indoors · Feb 2 – Feb 16
Broccoli, cabbageTransplant · Mar 23 – Apr 6
Onion setsPlant outdoors · Mar 16 – Mar 30
PotatoesPlant outdoors · Mar 23 – Apr 6
LettuceSow outdoors · Mar 16 – Mar 30
Carrots, beetsSow outdoors · Mar 23 – Apr 6
TomatoesStart indoors · Feb 16 – Mar 2
TomatoesTransplant · Apr 20 – May 4
Peppers, eggplantStart indoors · Feb 2 – Feb 16
Peppers, eggplantTransplant · Apr 27 – May 11
BeansSow outdoors · Apr 20 – May 4
Sweet cornSow outdoors · Apr 20 – May 4
Cucumbers, squashSow outdoors · Apr 20 – May 4
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 13) 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 45233 came on Mar 8 — 11 days earlier than the 1991–2020 average (Mar 19).

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 Cincinnati, OH.

Soil in Cincinnati, OH

The soil mapped at the center of ZIP 45233 is Eden — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.8neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Eden silty clay loam, 25 to 40 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 45233; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cincinnati, OH

Summer high86 °Faverage high, July
Winter low24 °Faverage low, January
Hot days22days a year at 90 °F or more
Freezing nights101nights a year at 32 °F or less
Growing degree days3,853base 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
Precipitation47.5 inper year, rain and melted snow
Snowfall11 inper year; 15 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 40 °F, low 24 °F 40°24° JanFebruary: average high 44 °F, low 26 °F 44°26° FebMarch: average high 54 °F, low 34 °F 54°34° MarApril: average high 66 °F, low 43 °F 66°43° AprMay: average high 75 °F, low 54 °F 75°54° MayJune: average high 83 °F, low 62 °F 83°62° JunJuly: average high 86 °F, low 67 °F 86°67° JulAugust: average high 85 °F, low 65 °F 85°65° AugSeptember: average high 79 °F, low 57 °F 79°57° SepOctober: average high 68 °F, low 46 °F 68°46° OctNovember: average high 55 °F, low 36 °F 55°36° NovDecember: average high 44 °F, low 29 °F 44°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.65 in precipitation, 2.9 in snowfall 3.6❄3 JanFebruary: 3.12 in precipitation, 4.7 in snowfall 3.1❄5 FebMarch: 4.37 in precipitation, 1.7 in snowfall 4.4❄2 MarApril: 4.96 in precipitation 5.0 AprMay: 5.15 in precipitation 5.2 MayJune: 4.78 in precipitation 4.8 JunJuly: 4.08 in precipitation 4.1 JulAugust: 3.34 in precipitation 3.3 AugSeptember: 3.31 in precipitation 3.3 SepOctober: 3.51 in precipitation 3.5 OctNovember: 3.19 in precipitation, 0.1 in snowfall 3.2 NovDecember: 4.03 in precipitation, 2 in snowfall 4.0❄2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cincinnati-Fernbank, OH (within 1 mile); precipitation: Cincinnati-Fernbank, OH (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

450516b
Mount Saint Joseph, OH · 2 mi
450016b
Addyston, OH · 3 mi
410486b
Hebron, KY · 3 mi
452486b
Cincinnati, OH · 3 mi
452386b
Cincinnati, OH · 3 mi
410256b
Erlanger, KY · 5 mi
452116b
Cincinnati, OH · 5 mi
452056b
Cincinnati, OH · 5 mi

All 70 ZIP codes in Cincinnati → · Ohio planting zones →

Questions about 45233

What planting zone is ZIP code 45233?

ZIP code 45233 (Cincinnati, 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 Cincinnati, OH?

The median last spring frost (32 °F) near 45233 is April 13; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cincinnati-Fernbank station.

When is the first frost in Cincinnati, OH?

The median first fall frost near 45233 is October 31, giving a median frost-free growing season of 197 days.

When should I plant tomatoes in 45233?

Start tomato seeds indoors around Feb 16 – Mar 2 and set transplants outside around Apr 20 – May 4, one to three weeks after the median last frost.

How much rain and snow does 45233 get?

About 47.5 inches of precipitation a year and 11 inches of snowfall (NOAA 1991–2020 normals, Cincinnati-Fernbank station).

How hot do summers get in Cincinnati, OH?

The average high peaks at 86 °F in July, with about 22 days a year at 90 °F or more.

What kind of soil does 45233 have?

The USDA soil survey maps Eden at the center of ZIP 45233: silty clay loam, well drained, pH about 6.8 (neutral).

Did spring come early in Cincinnati, OH in 2026?

Spring leaf-out near 45233 came on Mar 8 in 2026, 11 days earlier than the 1991–2020 average (Mar 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cincinnati, OH?

Intermediate onions: the longest day near 45233 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45233 change?

Yes. The 2012 USDA map put 45233 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.