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

Planting zone for 15106 — Carnegie, PA

ZIP code 15106 (Carnegie, Allegheny County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 24 and the first fall frost October 27.

Where ZIP 15106 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 24

First frostOct 27

2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Carnegie, 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 Carnegie, 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 27median — 10% chance by Oct 13

Growing season186 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 12 and returns around November 5.

From the NOAA station Emsworth L/D Ohio Rvr, PA — 7 miles away, elevation 719 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 15106

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 · Sep 1 – Sep 15

GarlicPlant cloves · Oct 13 – Nov 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 24) and first fall frost (Oct 27) 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 15106 came on Mar 10 — 17 days earlier than the 1991–2020 average (Mar 27).

average
Mar 272026
Mar 10

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 Carnegie, PA.

Soil in Carnegie, PA

The soil mapped at the center of ZIP 15106 is Dormont — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter2.6%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Dormont 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 15106; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Carnegie, PA

Summer high85 °Faverage high, July

Winter low21 °Faverage low, January

Hot days20days a year at 90 °F or more

Freezing nights107nights a year at 32 °F or less

Growing degree days3,337base 50 °F — the season’s usable heat

Longest day15 h 04 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)

Precipitation42.4 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: Emsworth L/D Ohio Rvr, PA (7 mi away); precipitation: Bridgeville 1.4 Sw, PA (5 mi away). 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.

151426b

Presto, PA · 2 mi

152056b

Pittsburgh, PA · 2 mi

152436b

Pittsburgh, PA · 3 mi

152206b

Pittsburgh, PA · 3 mi

151366b

Mc Kees Rocks, PA · 4 mi

152166b

Pittsburgh, PA · 4 mi

152047a

Pittsburgh, PA · 4 mi

150646b

Morgan, PA · 4 mi

Pennsylvania planting zones →

Questions about 15106

What planting zone is ZIP code 15106?

ZIP code 15106 (Carnegie, 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 Carnegie, PA?

The median last spring frost (32 °F) near 15106 is April 24; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Emsworth L/D Ohio Rvr station.

When is the first frost in Carnegie, PA?

The median first fall frost near 15106 is October 27, giving a median frost-free growing season of 186 days.

When should I plant tomatoes in 15106?

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 15106 get?

About 42.4 inches of precipitation a year (NOAA 1991–2020 normals, Bridgeville 1.4 Sw station).

How hot do summers get in Carnegie, PA?

The average high peaks at 85 °F in July, with about 20 days a year at 90 °F or more.

What kind of soil does 15106 have?

The USDA soil survey maps Dormont at the center of ZIP 15106: silt loam, moderately well drained, pH about 6.2 (slightly acidic).

Did spring come early in Carnegie, PA in 2026?

Spring leaf-out near 15106 came on Mar 10 in 2026, 17 days earlier than the 1991–2020 average (Mar 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Carnegie, PA?

Long-day onions: the longest day near 15106 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).