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

Planting zone for 45172 — Sinking Spring, OH

ZIP code 45172 (Sinking Spring, 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 45172 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 Sinking Spring, 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 Sinking Spring, 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 — 16 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 45172

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 45172 came on Mar 9 — 12 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 Sinking Spring, OH

The soil mapped at the center of ZIP 45172 is Opequon — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Opequon silt loam, 6 to 18 percent slopes, moderately eroded.

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 45172; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sinking Spring, 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 (16 mi away); precipitation: Hillsboro, OH (16 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

456466b
Latham, OH · 3 mi
456606b
Peebles, OH · 6 mi
456246b
Cynthiana, OH · 7 mi
456716b
Rarden, OH · 10 mi
456126b
Bainbridge, OH · 11 mi
451336b
Hillsboro, OH · 12 mi
456796b
Seaman, OH · 12 mi
456616b
Piketon, OH · 15 mi

Ohio planting zones →

Questions about 45172

What planting zone is ZIP code 45172?

ZIP code 45172 (Sinking Spring, 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 Sinking Spring, OH?

The median last spring frost (32 °F) near 45172 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 Sinking Spring, OH?

The median first fall frost near 45172 is October 20, giving a median frost-free growing season of 178 days.

When should I plant tomatoes in 45172?

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 45172 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 Sinking Spring, 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 45172 have?

The USDA soil survey maps Opequon at the center of ZIP 45172: silt loam, well drained, pH about 6.0 (slightly acidic).

Did spring come early in Sinking Spring, OH in 2026?

Spring leaf-out near 45172 came on Mar 9 in 2026, 12 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sinking Spring, OH?

Intermediate onions: the longest day near 45172 is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 45172 change?

Yes. The 2012 USDA map put 45172 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.