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

Planting zone for New Castle, PA

New Castle, PA is in USDA zones 6a to 6b across its 6 ZIP codes. The median last spring frost is April 30 and the first fall frost October 23.

New Castle on the zone map

Outlined: its 3 ZIP code areas · 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.

Zones6a–6b−10 to 0 °F
ZIP codes6
Last frostApr 30
First frostOct 23
Growing season175 days

6a 5 ZIPs   6b 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for New Castle, 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 New Castle, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 30median — 50% chance of a later frost
Safe for tender plantsMay 19only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 6
Growing season175 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 20 and returns around November 2.

From the NOAA station New Castle 1 N, PA, elevation 827 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 New Castle

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 19 – Apr 2
SpinachSow outdoors · Mar 19 – Apr 9
Broccoli, cabbageStart indoors · Feb 19 – Mar 5
Broccoli, cabbageTransplant · Apr 9 – Apr 23
Onion setsPlant outdoors · Apr 2 – Apr 16
PotatoesPlant outdoors · Apr 9 – Apr 23
LettuceSow outdoors · Apr 2 – Apr 16
Carrots, beetsSow outdoors · Apr 9 – Apr 23
TomatoesStart indoors · Mar 5 – Mar 19
TomatoesTransplant · May 7 – May 21
Peppers, eggplantStart indoors · Feb 19 – Mar 5
Peppers, eggplantTransplant · May 14 – May 28
BeansSow outdoors · May 7 – May 21
Sweet cornSow outdoors · May 7 – May 21
Cucumbers, squashSow outdoors · May 7 – May 21
Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 23) 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 16103 came on Mar 16 — 18 days earlier than the 1991–2020 average (Apr 3).

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 New Castle, PA.

Soil in New Castle, PA

The soil mapped at the center of ZIP 16103 is Canfield — slightly decomposed plant material, moderately well drained.

TextureSlightly decomposed plant materialtop layer
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter72%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Canfield silt loam, 15 to 25 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 16103; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Castle, PA

Summer high86 °Faverage high, July
Winter low19 °Faverage low, January
Hot days21days a year at 90 °F or more
Freezing nights134nights a year at 32 °F or less
Growing degree days3,088base 50 °F — the season’s usable heat
Longest day15 h 08 mindaylight on June 21
Shortest day9 h 13 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation41.8 inper year, rain and melted snow
Snowfall28 inper year; 42 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 19 °F 37°19° JanFebruary: average high 40 °F, low 20 °F 40°20° FebMarch: average high 49 °F, low 27 °F 49°27° MarApril: average high 63 °F, low 36 °F 63°36° AprMay: average high 73 °F, low 47 °F 73°47° MayJune: average high 82 °F, low 56 °F 82°56° JunJuly: average high 86 °F, low 60 °F 86°60° JulAugust: average high 85 °F, low 59 °F 85°59° AugSeptember: average high 79 °F, low 52 °F 79°52° SepOctober: average high 66 °F, low 41 °F 66°41° OctNovember: average high 53 °F, low 32 °F 53°32° NovDecember: average high 42 °F, low 25 °F 42°25° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.86 in precipitation, 10.1 in snowfall 2.9❄10 JanFebruary: 2.20 in precipitation, 7.7 in snowfall 2.2❄8 FebMarch: 3.08 in precipitation, 3.7 in snowfall 3.1❄4 MarApril: 3.65 in precipitation, 0.3 in snowfall 3.6 AprMay: 3.89 in precipitation 3.9 MayJune: 4.47 in precipitation 4.5 JunJuly: 4.55 in precipitation 4.5 JulAugust: 3.91 in precipitation 3.9 AugSeptember: 3.86 in precipitation 3.9 SepOctober: 3.22 in precipitation 3.2 OctNovember: 2.96 in precipitation, 0.8 in snowfall 3.0❄1 NovDecember: 3.13 in precipitation, 4.9 in snowfall 3.1❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: New Castle 1 N, PA (3 mi away); precipitation: New Castle 1 N, PA (3 mi away). Daylight is calculated from latitude.

ZIP codes in New Castle

161016a
−10 to −5 °F
161026a
−10 to −5 °F
161036b
−5 to 0 °F
161056a
−10 to −5 °F
161076a
−10 to −5 °F
161086a
−10 to −5 °F

Pennsylvania planting zones →

Questions about New Castle

What planting zone is New Castle, PA?

New Castle, PA is in USDA hardiness zones 6a to 6b on the 2023 map (6a: −10 to −5 °F; 6b: −5 to 0 °F).

When is the last frost in New Castle, PA?

The median last spring frost is April 30 and the median first fall frost is October 23 (NOAA 1991–2020 normals, New Castle 1 N station).

When can I plant a garden in New Castle, PA?

Cool-season crops like peas and spinach go in around Mar 19 – Apr 9; tomatoes, peppers, beans and squash after about May 7, once frost risk has passed.

What kind of onions grow in New Castle, PA?

Long-day onions: the longest day is 15 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does New Castle, PA get?

About 41.8 inches of precipitation a year and 28 inches of snowfall (NOAA 1991–2020 normals).