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

Planting zone for 15655 — Laughlintown, PA

ZIP code 15655 (Laughlintown, Westmoreland County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 26 and the first fall frost October 17.

Where ZIP 15655 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 frostApr 26
First frostOct 17
2012 zone6a

Same zone as on the 2012 map. 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 Laughlintown, 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 Laughlintown, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 26median — 50% chance of a later frost
Safe for tender plantsMay 13only 10% chance of frost after
First fall frostOctober 17median — 10% chance by Oct 4
Growing season172 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 16 and returns around October 29.

From the NOAA station Laurel Mtn, PA — within 1 mile, elevation 2,759 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 15655

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 15 – Mar 29
SpinachSow outdoors · Mar 15 – Apr 5
Broccoli, cabbageStart indoors · Feb 15 – Mar 1
Broccoli, cabbageTransplant · Apr 5 – Apr 19
Onion setsPlant outdoors · Mar 29 – Apr 12
PotatoesPlant outdoors · Apr 5 – Apr 19
LettuceSow outdoors · Mar 29 – Apr 12
Carrots, beetsSow outdoors · Apr 5 – Apr 19
TomatoesStart indoors · Mar 1 – Mar 15
TomatoesTransplant · May 3 – May 17
Peppers, eggplantStart indoors · Feb 15 – Mar 1
Peppers, eggplantTransplant · May 10 – May 24
BeansSow outdoors · May 3 – May 17
Sweet cornSow outdoors · May 3 – May 17
Cucumbers, squashSow outdoors · May 3 – May 17
Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5
GarlicPlant cloves · Oct 3 – Nov 7
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 26) and first fall frost (Oct 17) 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 15655 came on Mar 12 — 23 days earlier than the 1991–2020 average (Apr 4).

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 Laughlintown, PA.

Soil in Laughlintown, PA

The soil mapped at the center of ZIP 15655 is Laidig — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH4.3strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter69%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Laidig gravelly loam, 8 to 25 percent slopes, extremely 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 15655; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Laughlintown, PA

Summer high80 °Faverage high, July
Winter low19 °Faverage low, January
Hot days2days a year at 90 °F or more
Freezing nights126nights a year at 32 °F or less
Growing degree days2,654base 50 °F — the season’s usable heat
Longest day15 h 02 mindaylight on June 21
Shortest day9 h 18 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation49.6 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 39 °F, low 20 °F 39°20° FebMarch: average high 48 °F, low 27 °F 48°27° MarApril: average high 61 °F, low 38 °F 61°38° AprMay: average high 69 °F, low 48 °F 69°48° MayJune: average high 76 °F, low 57 °F 76°57° JunJuly: average high 80 °F, low 61 °F 80°61° JulAugust: average high 78 °F, low 59 °F 78°59° AugSeptember: average high 72 °F, low 52 °F 72°52° SepOctober: average high 62 °F, low 41 °F 62°41° OctNovember: average high 50 °F, low 33 °F 50°33° NovDecember: average high 41 °F, low 26 °F 41°26° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 4.13 in precipitation 4.1 JanFebruary: 3.26 in precipitation 3.3 FebMarch: 4.33 in precipitation 4.3 MarApril: 4.57 in precipitation 4.6 AprMay: 4.49 in precipitation 4.5 MayJune: 4.99 in precipitation 5.0 JunJuly: 4.73 in precipitation 4.7 JulAugust: 3.97 in precipitation 4.0 AugSeptember: 4.43 in precipitation 4.4 SepOctober: 3.62 in precipitation 3.6 OctNovember: 3.40 in precipitation 3.4 NovDecember: 3.64 in precipitation 3.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Laurel Mtn, PA (within 1 mile); precipitation: Laurel Mtn, PA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

156776a
Rector, PA · 4 mi
155316a
Boswell, PA · 5 mi
156586a
Ligonier, PA · 5 mi
155476a
Jennerstown, PA · 6 mi
155446a
Gray, PA · 6 mi
155466a
Jenners, PA · 8 mi
156876a
Stahlstown, PA · 8 mi
155615b
Sipesville, PA · 9 mi

Pennsylvania planting zones →

Questions about 15655

What planting zone is ZIP code 15655?

ZIP code 15655 (Laughlintown, 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 Laughlintown, PA?

The median last spring frost (32 °F) near 15655 is April 26; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Laurel Mtn station.

When is the first frost in Laughlintown, PA?

The median first fall frost near 15655 is October 17, giving a median frost-free growing season of 172 days.

When should I plant tomatoes in 15655?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 15655 get?

About 49.6 inches of precipitation a year (NOAA 1991–2020 normals, Laurel Mtn station).

How hot do summers get in Laughlintown, PA?

The average high peaks at 80 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 15655 have?

The USDA soil survey maps Laidig at the center of ZIP 15655: slightly decomposed plant material, well drained, pH about 4.3 (strongly acidic).

Did spring come early in Laughlintown, PA in 2026?

Spring leaf-out near 15655 came on Mar 12 in 2026, 23 days earlier than the 1991–2020 average (Apr 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Laughlintown, PA?

Long-day onions: the longest day near 15655 is 15 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).