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

Planting zone for 18073 — Pennsburg, PA

ZIP code 18073 (Pennsburg, Montgomery County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 26 and the first fall frost October 17.

Where ZIP 18073 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 26
First frostOct 17
2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Pennsburg, 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 Pennsburg, 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 12only 10% chance of frost after
First fall frostOctober 17median — 10% chance by Oct 5
Growing season175 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 28.

From the NOAA station Sellersville, PA — 9 miles away, elevation 302 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 18073

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 18073 came on Mar 26 — 3 days earlier than the 1991–2020 average (Mar 29).

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 7a in Pennsylvania

620 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 78

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 123

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 212

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 181

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 11

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °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 °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 Pennsburg, PA.

Soil in Pennsburg, PA

The soil mapped at the center of ZIP 18073 is Reaville — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Reaville 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 18073; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Pennsburg, PA

Summer high85 °Faverage high, July
Winter low19 °Faverage low, January
Hot days15days a year at 90 °F or more
Freezing nights131nights a year at 32 °F or less
Growing degree days3,059base 50 °F — the season’s usable heat
Longest day15 h 03 mindaylight on June 21
Shortest day9 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation49.1 inper year, rain and melted snow
Snowfall26 inper year; 27 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 38 °F, low 19 °F 38°19° JanFebruary: average high 41 °F, low 21 °F 41°21° FebMarch: average high 49 °F, low 28 °F 49°28° MarApril: average high 62 °F, low 38 °F 62°38° AprMay: average high 71 °F, low 48 °F 71°48° MayJune: average high 80 °F, low 57 °F 80°57° JunJuly: average high 85 °F, low 63 °F 85°63° JulAugust: average high 83 °F, low 61 °F 83°61° AugSeptember: average high 77 °F, low 54 °F 77°54° SepOctober: average high 64 °F, low 41 °F 64°41° OctNovember: average high 53 °F, low 32 °F 53°32° NovDecember: average high 43 °F, low 25 °F 43°25° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.41 in precipitation, 7.8 in snowfall 3.4❄8 JanFebruary: 2.90 in precipitation, 9.4 in snowfall 2.9❄9 FebMarch: 3.96 in precipitation, 4.4 in snowfall 4.0❄4 MarApril: 3.88 in precipitation, 1 in snowfall 3.9❄1 AprMay: 3.80 in precipitation 3.8 MayJune: 4.42 in precipitation 4.4 JunJuly: 5.43 in precipitation 5.4 JulAugust: 4.83 in precipitation 4.8 AugSeptember: 4.55 in precipitation 4.5 SepOctober: 4.62 in precipitation 4.6 OctNovember: 3.25 in precipitation, 0.3 in snowfall 3.3 NovDecember: 4.08 in precipitation, 3.4 in snowfall 4.1❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Sellersville, PA (9 mi away); precipitation: Palm 3 Se, PA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

180767a
Red Hill, PA · <1 mi
180417a
East Greenville, PA · 3 mi
180547a
Green Lane, PA · 3 mi
189687a
Spinnerstown, PA · 4 mi
180707a
Palm, PA · 5 mi
189707a
Trumbauersville, PA · 5 mi
189357a
Milford Square, PA · 5 mi
180747a
Perkiomenville, PA · 5 mi

Pennsylvania planting zones →

Questions about 18073

What planting zone is ZIP code 18073?

ZIP code 18073 (Pennsburg, PA) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Pennsburg, PA?

The median last spring frost (32 °F) near 18073 is April 26; after May 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sellersville station.

When is the first frost in Pennsburg, PA?

The median first fall frost near 18073 is October 17, giving a median frost-free growing season of 175 days.

When should I plant tomatoes in 18073?

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 18073 get?

About 49.1 inches of precipitation a year and 26 inches of snowfall (NOAA 1991–2020 normals, Palm 3 Se station).

How hot do summers get in Pennsburg, PA?

The average high peaks at 85 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 18073 have?

The USDA soil survey maps Reaville at the center of ZIP 18073: silt loam, moderately well drained, pH about 5.8 (moderately acidic).

Did spring come early in Pennsburg, PA in 2026?

Spring leaf-out near 18073 came on Mar 26 in 2026, 3 days earlier than the 1991–2020 average (Mar 29), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Pennsburg, PA?

Long-day onions: the longest day near 18073 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).