Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 15656 — Leechburg, PA

ZIP code 15656 (Leechburg, Armstrong 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 30.

Where ZIP 15656 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 30

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 Leechburg, 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 Leechburg, 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 30median — 10% chance by Oct 15

Growing season190 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around November 11.

From the NOAA station Schenley Lock 5, PA — 4 miles away, elevation 784 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 15656

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 · Sep 4 – Sep 18

GarlicPlant cloves · Oct 16 – Nov 20

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 21) and first fall frost (Oct 30) 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 15656 came on Mar 15 — 15 days earlier than the 1991–2020 average (Mar 30).

average
Mar 302026
Mar 15

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.

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 Leechburg, PA.

Soil in Leechburg, PA

The soil mapped at the center of ZIP 15656 is Gilpin — channery silt loam, well drained.

TextureChannery silt loama good balance for most vegetables

pH5.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.9%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Gilpin channery silt loam, 8 to 15 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 15656; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Leechburg, PA

Summer high84 °Faverage high, July

Winter low20 °Faverage low, January

Hot days26days a year at 90 °F or more

Freezing nights118nights a year at 32 °F or less

Growing degree days3,179base 50 °F — the season’s usable heat

Longest day15 h 05 mindaylight on June 21

Shortest day9 h 15 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

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Schenley Lock 5, PA (4 mi away); precipitation: Schenley Lock 5, PA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

Vandergrift, PA · 4 mi

156736b

North Apollo, PA · 5 mi

162296b

Freeport, PA · 5 mi

150656b

Natrona Heights, PA · 6 mi

150146b

Brackenridge, PA · 7 mi

156136b

Apollo, PA · 7 mi

Pennsylvania planting zones →

Questions about 15656

What planting zone is ZIP code 15656?

ZIP code 15656 (Leechburg, 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 Leechburg, PA?

The median last spring frost (32 °F) near 15656 is April 21; after May 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Schenley Lock 5 station.

When is the first frost in Leechburg, PA?

The median first fall frost near 15656 is October 30, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 15656?

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 15656 get?

About 43.5 inches of precipitation a year (NOAA 1991–2020 normals, Schenley Lock 5 station).

How hot do summers get in Leechburg, PA?

The average high peaks at 84 °F in July, with about 26 days a year at 90 °F or more.

What kind of soil does 15656 have?

The USDA soil survey maps Gilpin at the center of ZIP 15656: channery silt loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Leechburg, PA in 2026?

Spring leaf-out near 15656 came on Mar 15 in 2026, 15 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Leechburg, PA?

Long-day onions: the longest day near 15656 is 15 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 15656 change?

Yes. The 2012 USDA map put 15656 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.