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

Planting zone for 45050 — Monroe, OH

ZIP code 45050 (Monroe, Butler 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 19.

Where ZIP 45050 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 19
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 Monroe, 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 Monroe, 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 19median — 10% chance by Oct 7
Growing season178 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around October 29.

From the NOAA station Franklin, OH — 8 miles away, elevation 679 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 45050

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 24 – Sep 7
GarlicPlant cloves · Oct 5 – Nov 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 24) and first fall frost (Oct 19) 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 45050 came on Mar 10 — 11 days earlier than the 1991–2020 average (Mar 21).

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).

Soil in Monroe, OH

The soil mapped at the center of ZIP 45050 is Russell — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.25%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Russell-Urban land complex, gently sloping.

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 45050; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Monroe, OH

Summer high86 °Faverage high, July
Winter low20 °Faverage low, January
Hot days22days a year at 90 °F or more
Freezing nights120nights a year at 32 °F or less
Growing degree days3,407base 50 °F — the season’s usable heat
Longest day14 h 57 mindaylight on June 21
Shortest day9 h 23 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation42 inper year, rain and melted snow
Snowfall10 inper year; 12 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 38 °F, low 20 °F 38°20° JanFebruary: average high 42 °F, low 22 °F 42°22° FebMarch: average high 52 °F, low 30 °F 52°30° MarApril: average high 65 °F, low 39 °F 65°39° AprMay: average high 74 °F, low 51 °F 74°51° MayJune: average high 82 °F, low 60 °F 82°60° JunJuly: average high 86 °F, low 64 °F 86°64° JulAugust: average high 85 °F, low 61 °F 85°61° AugSeptember: average high 79 °F, low 53 °F 79°53° SepOctober: average high 67 °F, low 41 °F 67°41° OctNovember: average high 53 °F, low 32 °F 53°32° NovDecember: average high 43 °F, low 26 °F 43°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.16 in precipitation, 4.7 in snowfall 3.2❄5 JanFebruary: 2.44 in precipitation, 1.9 in snowfall 2.4❄2 FebMarch: 3.69 in precipitation, 1.5 in snowfall 3.7❄2 MarApril: 4.42 in precipitation 4.4 AprMay: 4.34 in precipitation 4.3 MayJune: 4.46 in precipitation 4.5 JunJuly: 3.65 in precipitation 3.6 JulAugust: 3.42 in precipitation 3.4 AugSeptember: 2.93 in precipitation 2.9 SepOctober: 3.14 in precipitation 3.1 OctNovember: 3.01 in precipitation, 0.2 in snowfall 3.0 NovDecember: 3.39 in precipitation, 1.4 in snowfall 3.4❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Franklin, OH (8 mi away); precipitation: Middletown, OH (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

450446b
Middletown, OH · 4 mi
450406b
Mason, OH · 7 mi
450676b
Trenton, OH · 7 mi
450056b
Franklin, OH · 7 mi
450116b
Hamilton, OH · 7 mi
450696b
West Chester, OH · 7 mi
450556b
Overpeck, OH · 8 mi
450366b
Lebanon, OH · 8 mi

Ohio planting zones →

Questions about 45050

What planting zone is ZIP code 45050?

ZIP code 45050 (Monroe, 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 Monroe, OH?

The median last spring frost (32 °F) near 45050 is April 24; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Franklin station.

When is the first frost in Monroe, OH?

The median first fall frost near 45050 is October 19, giving a median frost-free growing season of 178 days.

When should I plant tomatoes in 45050?

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 45050 get?

About 42 inches of precipitation a year and 10 inches of snowfall (NOAA 1991–2020 normals, Middletown station).

How hot do summers get in Monroe, 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 45050 have?

The USDA soil survey maps Russell at the center of ZIP 45050: silt loam, well drained, pH about 6.5 (neutral).

Did spring come early in Monroe, OH in 2026?

Spring leaf-out near 45050 came on Mar 10 in 2026, 11 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Monroe, OH?

Intermediate onions: the longest day near 45050 is 14 h 57 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45050 change?

Yes. The 2012 USDA map put 45050 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.