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

Planting zone for 45203 — Cincinnati, OH

ZIP code 45203 (Cincinnati, Hamilton County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 17 and the first fall frost October 26.

Where ZIP 45203 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 17
First frostOct 26
2012 zone6b

Same zone as on the 2012 map. 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 17median — 50% chance of a later frost
Safe for tender plantsMay 5only 10% chance of frost after
First fall frostOctober 26median — 10% chance by Oct 11
Growing season191 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 4.

From the NOAA station Cheviot, OH — 6 miles away, elevation 892 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 45203

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 6 – Mar 20
SpinachSow outdoors · Mar 6 – Mar 27
Broccoli, cabbageStart indoors · Feb 6 – Feb 20
Broccoli, cabbageTransplant · Mar 27 – Apr 10
Onion setsPlant outdoors · Mar 20 – Apr 3
PotatoesPlant outdoors · Mar 27 – Apr 10
LettuceSow outdoors · Mar 20 – Apr 3
Carrots, beetsSow outdoors · Mar 27 – Apr 10
TomatoesStart indoors · Feb 20 – Mar 6
TomatoesTransplant · Apr 24 – May 8
Peppers, eggplantStart indoors · Feb 6 – Feb 20
Peppers, eggplantTransplant · May 1 – May 15
BeansSow outdoors · Apr 24 – May 8
Sweet cornSow outdoors · Apr 24 – May 8
Cucumbers, squashSow outdoors · Apr 24 – May 8
Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14
GarlicPlant cloves · Oct 12 – Nov 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 26) 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 45203 came on Mar 10 — 7 days earlier than the 1991–2020 average (Mar 17).

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 center of ZIP 45203 is mapped as Urban land, 0 to 12 percent slopes, occasionally flooded: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 45203; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cincinnati, OH

Summer high85 °Faverage high, July
Winter low22 °Faverage low, January
Hot days26days a year at 90 °F or more
Freezing nights106nights a year at 32 °F or less
Growing degree days3,702base 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
Snowfall16 inper year; 27 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 37 °F, low 22 °F 37°22° JanFebruary: average high 42 °F, low 25 °F 42°25° FebMarch: average high 52 °F, low 33 °F 52°33° MarApril: average high 65 °F, low 43 °F 65°43° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 82 °F, low 62 °F 82°62° JunJuly: average high 85 °F, low 65 °F 85°65° JulAugust: average high 85 °F, low 64 °F 85°64° AugSeptember: average high 78 °F, low 57 °F 78°57° SepOctober: average high 66 °F, low 45 °F 66°45° OctNovember: average high 53 °F, low 35 °F 53°35° NovDecember: average high 42 °F, low 27 °F 42°27° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.59 in precipitation, 6 in snowfall 3.6❄6 JanFebruary: 3.19 in precipitation, 4.3 in snowfall 3.2❄4 FebMarch: 4.47 in precipitation, 2.4 in snowfall 4.5❄2 MarApril: 4.91 in precipitation, 0.2 in snowfall 4.9 AprMay: 5.21 in precipitation 5.2 MayJune: 4.85 in precipitation 4.8 JunJuly: 4.32 in precipitation 4.3 JulAugust: 3.47 in precipitation 3.5 AugSeptember: 3.32 in precipitation 3.3 SepOctober: 3.47 in precipitation, 0.3 in snowfall 3.5 OctNovember: 3.42 in precipitation, 0.2 in snowfall 3.4 NovDecember: 3.96 in precipitation, 2.6 in snowfall 4.0❄3 Dec

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

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

452146b
Cincinnati, OH · <1 mi
410166b
Covington, KY · 1 mi
452026b
Cincinnati, OH · 2 mi
452196b
Cincinnati, OH · 2 mi
452056b
Cincinnati, OH · 2 mi
452046b
Cincinnati, OH · 3 mi
410116b
Covington, KY · 3 mi
452676b
Cincinnati, OH · 3 mi

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

Questions about 45203

What planting zone is ZIP code 45203?

ZIP code 45203 (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 45203 is April 17; after May 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cheviot station.

When is the first frost in Cincinnati, OH?

The median first fall frost near 45203 is October 26, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 45203?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 45203 get?

About 48.2 inches of precipitation a year and 16 inches of snowfall (NOAA 1991–2020 normals, Cheviot station).

How hot do summers get in Cincinnati, OH?

The average high peaks at 85 °F in July, with about 26 days a year at 90 °F or more.

Did spring come early in Cincinnati, OH in 2026?

Spring leaf-out near 45203 came on Mar 10 in 2026, 7 days earlier than the 1991–2020 average (Mar 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cincinnati, OH?

Intermediate onions: the longest day near 45203 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.