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

Planting zone for 16253 — Seminole, PA

ZIP code 16253 (Seminole, Armstrong County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 10 and the first fall frost October 12.

Where ZIP 16253 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 frostMay 10

First frostOct 12

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 Seminole, 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 Seminole, PA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 10median — 50% chance of a later frost

Safe for tender plantsMay 28only 10% chance of frost after

First fall frostOctober 12median — 10% chance by Sep 30

Growing season155 daysfrost-free, median

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

From the NOAA station Putneyville 2 Se Dam, PA — 4 miles away, elevation 1,280 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 16253

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 29 – Apr 12

SpinachSow outdoors · Mar 29 – Apr 19

Broccoli, cabbageStart indoors · Mar 1 – Mar 15

Broccoli, cabbageTransplant · Apr 19 – May 3

Onion setsPlant outdoors · Apr 12 – Apr 26

PotatoesPlant outdoors · Apr 19 – May 3

LettuceSow outdoors · Apr 12 – Apr 26

Carrots, beetsSow outdoors · Apr 19 – May 3

TomatoesStart indoors · Mar 15 – Mar 29

TomatoesTransplant · May 17 – May 31

Peppers, eggplantStart indoors · Mar 1 – Mar 15

Peppers, eggplantTransplant · May 24 – Jun 7

BeansSow outdoors · May 17 – May 31

Sweet cornSow outdoors · May 17 – May 31

Cucumbers, squashSow outdoors · May 17 – May 31

Fall lettuce, spinachSow outdoors · Aug 17 – Aug 31

GarlicPlant cloves · Sep 28 – Nov 2

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 10) and first fall frost (Oct 12) 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 16253 came on Mar 21 — 15 days earlier than the 1991–2020 average (Apr 5).

average
Apr 52026
Mar 21

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).

Soil in Seminole, PA

The soil mapped at the center of ZIP 16253 is Wharton — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables

pH5.6moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Wharton-Gilpin silt loams, 15 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 16253; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Seminole, PA

Summer high82 °Faverage high, July

Winter low17 °Faverage low, January

Hot days7days a year at 90 °F or more

Freezing nights152nights a year at 32 °F or less

Growing degree days2,597base 50 °F — the season’s usable heat

Longest day15 h 07 mindaylight on June 21

Shortest day9 h 13 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation45.7 inper year, rain and melted snow

Snowfall35 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Putneyville 2 Se Dam, PA (4 mi away); precipitation: Putneyville 2 Se Dam, PA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

162236a

Distant, PA · 2 mi

162426a

New Bethlehem, PA · 2 mi

Pennsylvania planting zones →

Questions about 16253

What planting zone is ZIP code 16253?

ZIP code 16253 (Seminole, 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 Seminole, PA?

The median last spring frost (32 °F) near 16253 is May 10; after May 28 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Putneyville 2 Se Dam station.

When is the first frost in Seminole, PA?

The median first fall frost near 16253 is October 12, giving a median frost-free growing season of 155 days.

When should I plant tomatoes in 16253?

Start tomato seeds indoors around Mar 15 – Mar 29 and set transplants outside around May 17 – May 31, one to three weeks after the median last frost.

How much rain and snow does 16253 get?

About 45.7 inches of precipitation a year and 35 inches of snowfall (NOAA 1991–2020 normals, Putneyville 2 Se Dam station).

How hot do summers get in Seminole, 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 16253 have?

The USDA soil survey maps Wharton at the center of ZIP 16253: silt loam, moderately well drained, pH about 5.6 (moderately acidic).

Did spring come early in Seminole, PA in 2026?

Spring leaf-out near 16253 came on Mar 21 in 2026, 15 days earlier than the 1991–2020 average (Apr 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Seminole, PA?

Long-day onions: the longest day near 16253 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 16253 change?

Yes. The 2012 USDA map put 16253 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.