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

Planting zone for 17701 — Williamsport, PA

ZIP code 17701 (Williamsport, Lycoming County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 24 and the first fall frost October 23.

Where ZIP 17701 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 24
First frostOct 23
2012 zone6b

Was 6b on the 2012 map — half a zone colder 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 Williamsport, 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 Williamsport, PA

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 23median — 10% chance by Oct 6
Growing season180 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 12 and returns around November 3.

From the NOAA station Williamsport, PA — 8 miles away, elevation 522 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 17701

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 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 24) 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 17701 came on Apr 3 — 8 days earlier than the 1991–2020 average (Apr 11).

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 Williamsport, PA.

Soil in Williamsport, PA

The soil mapped at the center of ZIP 17701 is Dekalb — very channery loam, well drained.

TextureVery channery loama good balance for most vegetables
pH5.1strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Dekalb very stony sandy loam, 8 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 17701; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Williamsport, PA

Summer high85 °Faverage high, July
Winter low20 °Faverage low, January
Hot days17days a year at 90 °F or more
Freezing nights122nights a year at 32 °F or less
Growing degree days3,083base 50 °F — the season’s usable heat
Longest day15 h 10 mindaylight on June 21
Shortest day9 h 11 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation43.5 inper year, rain and melted snow
Snowfall36 inper year; 37 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 35 °F, low 20 °F 35°20° JanFebruary: average high 39 °F, low 22 °F 39°22° FebMarch: average high 48 °F, low 29 °F 48°29° MarApril: average high 62 °F, low 39 °F 62°39° AprMay: average high 72 °F, low 49 °F 72°49° MayJune: average high 81 °F, low 58 °F 81°58° JunJuly: average high 85 °F, low 63 °F 85°63° JulAugust: average high 83 °F, low 61 °F 83°61° AugSeptember: average high 75 °F, low 54 °F 75°54° SepOctober: average high 63 °F, low 43 °F 63°43° OctNovember: average high 51 °F, low 33 °F 51°33° NovDecember: average high 40 °F, low 26 °F 40°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.96 in precipitation, 9.7 in snowfall 3.0❄10 JanFebruary: 2.31 in precipitation, 9.3 in snowfall 2.3❄9 FebMarch: 3.13 in precipitation, 7.3 in snowfall 3.1❄7 MarApril: 3.62 in precipitation, 0.8 in snowfall 3.6❄1 AprMay: 3.86 in precipitation 3.9 MayJune: 3.85 in precipitation 3.9 JunJuly: 4.64 in precipitation 4.6 JulAugust: 4.17 in precipitation 4.2 AugSeptember: 4.76 in precipitation 4.8 SepOctober: 3.70 in precipitation, 0.1 in snowfall 3.7 OctNovember: 3.25 in precipitation, 1.7 in snowfall 3.3❄2 NovDecember: 3.27 in precipitation, 6.9 in snowfall 3.3❄7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Williamsport, PA (8 mi away); precipitation: Williamsport, PA (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

177546b
Montoursville, PA · 3 mi
177056b
Williamsport, PA · 9 mi
177626b
Picture Rocks, PA · 9 mi
186196a
Hillsgrove, PA · 10 mi
177376b
Hughesville, PA · 10 mi
177036b
Williamsport, PA · 10 mi
177716a
Trout Run, PA · 11 mi
177636a
Ralston, PA · 11 mi

All 4 ZIP codes in Williamsport → · Pennsylvania planting zones →

Questions about 17701

What planting zone is ZIP code 17701?

ZIP code 17701 (Williamsport, 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 Williamsport, PA?

The median last spring frost (32 °F) near 17701 is April 24; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Williamsport station.

When is the first frost in Williamsport, PA?

The median first fall frost near 17701 is October 23, giving a median frost-free growing season of 180 days.

When should I plant tomatoes in 17701?

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 17701 get?

About 43.5 inches of precipitation a year and 36 inches of snowfall (NOAA 1991–2020 normals, Williamsport station).

How hot do summers get in Williamsport, PA?

The average high peaks at 85 °F in July, with about 17 days a year at 90 °F or more.

What kind of soil does 17701 have?

The USDA soil survey maps Dekalb at the center of ZIP 17701: very channery loam, well drained, pH about 5.1 (strongly acidic).

Did spring come early in Williamsport, PA in 2026?

Spring leaf-out near 17701 came on Apr 3 in 2026, 8 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Williamsport, PA?

Long-day onions: the longest day near 17701 is 15 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 17701 change?

Yes. The 2012 USDA map put 17701 in zone 6b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.