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

Planting zone for 16003 — Butler, PA

ZIP code 16003 (Butler, Butler County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 7 and the first fall frost October 14.

Where ZIP 16003 is

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 frostMay 7
First frostOct 14
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 Butler, 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 Butler, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 7median — 50% chance of a later frost
Safe for tender plantsMay 23only 10% chance of frost after
First fall frostOctober 14median — 10% chance by Oct 1
Growing season159 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 26 and returns around October 27.

From the NOAA station Butler 2 Sw, PA — 2 miles away, elevation 1,001 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 16003

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 26 – Apr 9
SpinachSow outdoors · Mar 26 – Apr 16
Broccoli, cabbageStart indoors · Feb 26 – Mar 12
Broccoli, cabbageTransplant · Apr 16 – Apr 30
Onion setsPlant outdoors · Apr 9 – Apr 23
PotatoesPlant outdoors · Apr 16 – Apr 30
LettuceSow outdoors · Apr 9 – Apr 23
Carrots, beetsSow outdoors · Apr 16 – Apr 30
TomatoesStart indoors · Mar 12 – Mar 26
TomatoesTransplant · May 14 – May 28
Peppers, eggplantStart indoors · Feb 26 – Mar 12
Peppers, eggplantTransplant · May 21 – Jun 4
BeansSow outdoors · May 14 – May 28
Sweet cornSow outdoors · May 14 – May 28
Cucumbers, squashSow outdoors · May 14 – May 28
Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2
GarlicPlant cloves · Sep 30 – Nov 4
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 7) and first fall frost (Oct 14) 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 16003 came on Mar 16 — 18 days earlier than the 1991–2020 average (Apr 3).

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.

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 122

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 209

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 173

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 10

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 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °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 Butler, PA.

Soil in Butler, PA

The soil mapped at the center of ZIP 16003 is Ernest — silt loam, moderately well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSilt loama good balance for most vegetables
pH5.4strongly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter3%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Ernest complex, 0 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 16003; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Butler, PA

Summer high82 °Faverage high, July
Winter low17 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights140nights a year at 32 °F or less
Growing degree days2,533base 50 °F — the season’s usable heat
Longest day15 h 07 mindaylight on June 21
Shortest day9 h 14 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation43.2 inper year, rain and melted snow
Snowfall35 inper year; 53 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 34 °F, low 17 °F 34°17° JanFebruary: average high 37 °F, low 18 °F 37°18° FebMarch: average high 46 °F, low 25 °F 46°25° MarApril: average high 60 °F, low 35 °F 60°35° AprMay: average high 70 °F, low 45 °F 70°45° MayJune: average high 78 °F, low 54 °F 78°54° JunJuly: average high 82 °F, low 58 °F 82°58° JulAugust: average high 81 °F, low 57 °F 81°57° AugSeptember: average high 74 °F, low 50 °F 74°50° SepOctober: average high 62 °F, low 39 °F 62°39° OctNovember: average high 50 °F, low 30 °F 50°30° NovDecember: average high 39 °F, low 23 °F 39°23° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.36 in precipitation, 11.3 in snowfall 3.4❄11 JanFebruary: 2.66 in precipitation, 9.7 in snowfall 2.7❄10 FebMarch: 3.28 in precipitation, 5.3 in snowfall 3.3❄5 MarApril: 3.50 in precipitation, 0.6 in snowfall 3.5❄1 AprMay: 3.80 in precipitation 3.8 MayJune: 4.33 in precipitation 4.3 JunJuly: 4.16 in precipitation 4.2 JulAugust: 4.02 in precipitation 4.0 AugSeptember: 4.09 in precipitation 4.1 SepOctober: 3.30 in precipitation, 0.1 in snowfall 3.3 OctNovember: 3.34 in precipitation, 1.1 in snowfall 3.3❄1 NovDecember: 3.37 in precipitation, 6.8 in snowfall 3.4❄7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Butler 2 Sw, PA (2 mi away); precipitation: Butler 2 Sw, PA (2 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.

160456b
Lyndora, PA · 1 mi
160296a
East Butler, PA · 3 mi
160026a
Butler, PA · 4 mi
160016a
Butler, PA · 4 mi
160176a
Boyers, PA · 4 mi
160186a
Boyers, PA · 4 mi
160396b
Herman, PA · 5 mi
160536b
Renfrew, PA · 6 mi

All 3 ZIP codes in Butler → · Pennsylvania planting zones →

Questions about 16003

What planting zone is ZIP code 16003?

ZIP code 16003 (Butler, 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 Butler, PA?

The median last spring frost (32 °F) near 16003 is May 7; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Butler 2 Sw station.

When is the first frost in Butler, PA?

The median first fall frost near 16003 is October 14, giving a median frost-free growing season of 159 days.

When should I plant tomatoes in 16003?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 16003 get?

About 43.2 inches of precipitation a year and 35 inches of snowfall (NOAA 1991–2020 normals, Butler 2 Sw station).

How hot do summers get in Butler, PA?

The average high peaks at 82 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 16003 have?

The USDA soil survey maps Ernest at the center of ZIP 16003: silt loam, moderately well drained, pH about 5.4 (strongly acidic).

Did spring come early in Butler, PA in 2026?

Spring leaf-out near 16003 came on Mar 16 in 2026, 18 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Butler, PA?

Long-day onions: the longest day near 16003 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 16003 change?

Yes. The 2012 USDA map put 16003 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.