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

Planting zone for 16435 — Springboro, PA

ZIP code 16435 (Springboro, Crawford County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 8 and the first fall frost October 16.

Where ZIP 16435 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostMay 8
First frostOct 16
2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Springboro, PA…

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 Springboro, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 8median — 50% chance of a later frost
Safe for tender plantsMay 23only 10% chance of frost after
First fall frostOctober 16median — 10% chance by Oct 1
Growing season160 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 26 and returns around November 1.

From the NOAA station Springboro 3 Wnw, PA — 2 miles away, elevation 1,004 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 16435

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 27 – Apr 10
SpinachSow outdoors · Mar 27 – Apr 17
Broccoli, cabbageStart indoors · Feb 27 – Mar 13
Broccoli, cabbageTransplant · Apr 17 – May 1
Onion setsPlant outdoors · Apr 10 – Apr 24
PotatoesPlant outdoors · Apr 17 – May 1
LettuceSow outdoors · Apr 10 – Apr 24
Carrots, beetsSow outdoors · Apr 17 – May 1
TomatoesStart indoors · Mar 13 – Mar 27
TomatoesTransplant · May 15 – May 29
Peppers, eggplantStart indoors · Feb 27 – Mar 13
Peppers, eggplantTransplant · May 22 – Jun 5
BeansSow outdoors · May 15 – May 29
Sweet cornSow outdoors · May 15 – May 29
Cucumbers, squashSow outdoors · May 15 – May 29
Fall lettuce, spinachSow outdoors · Aug 21 – Sep 4
GarlicPlant cloves · Oct 2 – Nov 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 8) and first fall frost (Oct 16) 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 16435 came on Mar 26 — 14 days earlier than the 1991–2020 average (Apr 9).

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 6a in Pennsylvania

598 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 76

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 121

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 207

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 170

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 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 9

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 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Springboro, PA.

Soil in Springboro, PA

The soil mapped at the center of ZIP 16435 is Venango — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter4.2%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Venango silt loam, 3 to 8 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 16435; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Springboro, PA

Summer high80 °Faverage high, July
Winter low17 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights141nights a year at 32 °F or less
Growing degree days2,397base 50 °F — the season’s usable heat
Longest day15 h 13 mindaylight on June 21
Shortest day9 h 08 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation48.2 inper year, rain and melted snow
Snowfall111 inper year; 81 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 17 °F 32°17° JanFebruary: average high 34 °F, low 17 °F 34°17° FebMarch: average high 43 °F, low 24 °F 43°24° MarApril: average high 57 °F, low 34 °F 57°34° AprMay: average high 68 °F, low 44 °F 68°44° MayJune: average high 76 °F, low 54 °F 76°54° JunJuly: average high 80 °F, low 58 °F 80°58° JulAugust: average high 79 °F, low 57 °F 79°57° AugSeptember: average high 73 °F, low 50 °F 73°50° SepOctober: average high 61 °F, low 41 °F 61°41° OctNovember: average high 48 °F, low 32 °F 48°32° NovDecember: average high 37 °F, low 24 °F 37°24° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.59 in precipitation, 38 in snowfall 3.6❄38 JanFebruary: 2.59 in precipitation, 19 in snowfall 2.6❄19 FebMarch: 3.37 in precipitation, 13.6 in snowfall 3.4❄14 MarApril: 3.99 in precipitation, 3.5 in snowfall 4.0❄4 AprMay: 4.19 in precipitation 4.2 MayJune: 4.69 in precipitation 4.7 JunJuly: 4.44 in precipitation 4.4 JulAugust: 4.09 in precipitation 4.1 AugSeptember: 4.59 in precipitation 4.6 SepOctober: 4.75 in precipitation, 0.5 in snowfall 4.8❄1 OctNovember: 4.01 in precipitation, 10.2 in snowfall 4.0❄10 NovDecember: 3.90 in precipitation, 26.2 in snowfall 3.9❄26 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Springboro 3 Wnw, PA (2 mi away); precipitation: Springboro 3 Wnw, PA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

164756a
Albion, PA · 4 mi
164016a
Albion, PA · 4 mi
164066a
Conneautville, PA · 5 mi
164106a
Cranesville, PA · 8 mi
164436b
West Springfield, PA · 9 mi
440826a
Pierpont, OH · 10 mi
164176b
Girard, PA · 11 mi
164116b
East Springfield, PA · 11 mi

Pennsylvania planting zones →

Questions about 16435

What planting zone is ZIP code 16435?

ZIP code 16435 (Springboro, PA) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Springboro, PA?

The median last spring frost (32 °F) near 16435 is May 8; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Springboro 3 Wnw station.

When is the first frost in Springboro, PA?

The median first fall frost near 16435 is October 16, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 16435?

Start tomato seeds indoors around Mar 13 – Mar 27 and set transplants outside around May 15 – May 29, one to three weeks after the median last frost.

How much rain and snow does 16435 get?

About 48.2 inches of precipitation a year and 111 inches of snowfall (NOAA 1991–2020 normals, Springboro 3 Wnw station).

How hot do summers get in Springboro, PA?

The average high peaks at 80 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 16435 have?

The USDA soil survey maps Venango at the center of ZIP 16435: silt loam, somewhat poorly drained, pH about 5.0 (strongly acidic).

Did spring come early in Springboro, PA in 2026?

Spring leaf-out near 16435 came on Mar 26 in 2026, 14 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Springboro, PA?

Long-day onions: the longest day near 16435 is 15 h 13 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 16435 change?

Yes. The 2012 USDA map put 16435 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.