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

Planting zone for 18250 — Summit Hill, PA

ZIP code 18250 (Summit Hill, Carbon County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 21 and the first fall frost October 23.

Where ZIP 18250 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 21
First frostOct 23
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 Summit Hill, 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 Summit Hill, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 21median — 50% chance of a later frost
Safe for tender plantsMay 9only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 7
Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around November 4.

From the NOAA station Lehighton 1ssw, PA — 9 miles away, elevation 456 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 18250

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 10 – Mar 24
SpinachSow outdoors · Mar 10 – Mar 31
Broccoli, cabbageStart indoors · Feb 10 – Feb 24
Broccoli, cabbageTransplant · Mar 31 – Apr 14
Onion setsPlant outdoors · Mar 24 – Apr 7
PotatoesPlant outdoors · Mar 31 – Apr 14
LettuceSow outdoors · Mar 24 – Apr 7
Carrots, beetsSow outdoors · Mar 31 – Apr 14
TomatoesStart indoors · Feb 24 – Mar 10
TomatoesTransplant · Apr 28 – May 12
Peppers, eggplantStart indoors · Feb 10 – Feb 24
Peppers, eggplantTransplant · May 5 – May 19
BeansSow outdoors · Apr 28 – May 12
Sweet cornSow outdoors · Apr 28 – May 12
Cucumbers, squashSow outdoors · Apr 28 – May 12
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 21) 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 18250 came on Apr 2 — 7 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 6b in Pennsylvania

605 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 122

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 209

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 173

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °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 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °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 Summit Hill, PA.

Soil in Summit Hill, PA

The soil mapped at the center of ZIP 18250 is Dekalb — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH4.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter85%high
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Dekalb very stony loam, 25 to 100 percent slopes, very stony.

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 18250; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Summit Hill, PA

Summer high82 °Faverage high, July
Winter low19 °Faverage low, January
Hot days4days a year at 90 °F or more
Freezing nights132nights a year at 32 °F or less
Growing degree days2,748base 50 °F — the season’s usable heat
Longest day15 h 06 mindaylight on June 21
Shortest day9 h 14 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation51.3 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 36 °F, low 19 °F 36°19° JanFebruary: average high 38 °F, low 21 °F 38°21° FebMarch: average high 47 °F, low 28 °F 47°28° MarApril: average high 61 °F, low 38 °F 61°38° AprMay: average high 71 °F, low 48 °F 71°48° MayJune: average high 78 °F, low 57 °F 78°57° JunJuly: average high 82 °F, low 62 °F 82°62° JulAugust: average high 80 °F, low 60 °F 80°60° AugSeptember: average high 73 °F, low 53 °F 73°53° SepOctober: average high 62 °F, low 41 °F 62°41° OctNovember: average high 50 °F, low 32 °F 50°32° NovDecember: average high 40 °F, low 24 °F 40°24° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.48 in precipitation 3.5 JanFebruary: 2.86 in precipitation 2.9 FebMarch: 3.82 in precipitation 3.8 MarApril: 4.04 in precipitation 4.0 AprMay: 4.42 in precipitation 4.4 MayJune: 4.96 in precipitation 5.0 JunJuly: 4.93 in precipitation 4.9 JulAugust: 4.82 in precipitation 4.8 AugSeptember: 5.19 in precipitation 5.2 SepOctober: 4.78 in precipitation 4.8 OctNovember: 3.75 in precipitation 3.8 NovDecember: 4.28 in precipitation 4.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lehighton 1ssw, PA (9 mi away); precipitation: Lehighton 3.3 Wsw, PA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

182326b
Lansford, PA · 2 mi
182186b
Coaldale, PA · 3 mi
182406b
Nesquehoning, PA · 4 mi
182116b
Andreas, PA · 5 mi
182526b
Tamaqua, PA · 6 mi
182126b
Ashfield, PA · 8 mi
182306b
Junedale, PA · 8 mi
182556b
Weatherly, PA · 8 mi

Pennsylvania planting zones →

Questions about 18250

What planting zone is ZIP code 18250?

ZIP code 18250 (Summit Hill, PA) 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 Summit Hill, PA?

The median last spring frost (32 °F) near 18250 is April 21; after May 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lehighton 1ssw station.

When is the first frost in Summit Hill, PA?

The median first fall frost near 18250 is October 23, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 18250?

Start tomato seeds indoors around Feb 24 – Mar 10 and set transplants outside around Apr 28 – May 12, one to three weeks after the median last frost.

How much rain and snow does 18250 get?

About 51.3 inches of precipitation a year (NOAA 1991–2020 normals, Lehighton 3.3 Wsw station).

How hot do summers get in Summit Hill, PA?

The average high peaks at 82 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 18250 have?

The USDA soil survey maps Dekalb at the center of ZIP 18250: slightly decomposed plant material, well drained, pH about 4.0 (strongly acidic).

Did spring come early in Summit Hill, PA in 2026?

Spring leaf-out near 18250 came on Apr 2 in 2026, 7 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Summit Hill, PA?

Long-day onions: the longest day near 18250 is 15 h 06 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 18250 change?

Yes. The 2012 USDA map put 18250 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.