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

Planting zone for 18831 — Milan, PA

ZIP code 18831 (Milan, Bradford County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 6 and the first fall frost October 10.

Where ZIP 18831 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostMay 6
First frostOct 10
2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Milan, 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 Milan, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 6median — 50% chance of a later frost
Safe for tender plantsMay 22only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 27
Growing season157 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 25.

From the NOAA station Waverly, NY — 8 miles away, elevation 846 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 18831

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 25 – Apr 8
SpinachSow outdoors · Mar 25 – Apr 15
Broccoli, cabbageStart indoors · Feb 25 – Mar 11
Broccoli, cabbageTransplant · Apr 15 – Apr 29
Onion setsPlant outdoors · Apr 8 – Apr 22
PotatoesPlant outdoors · Apr 15 – Apr 29
LettuceSow outdoors · Apr 8 – Apr 22
Carrots, beetsSow outdoors · Apr 15 – Apr 29
TomatoesStart indoors · Mar 11 – Mar 25
TomatoesTransplant · May 13 – May 27
Peppers, eggplantStart indoors · Feb 25 – Mar 11
Peppers, eggplantTransplant · May 20 – Jun 3
BeansSow outdoors · May 13 – May 27
Sweet cornSow outdoors · May 13 – May 27
Cucumbers, squashSow outdoors · May 13 – May 27
Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 10) 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 18831 came on Apr 6 — 6 days earlier than the 1991–2020 average (Apr 12).

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 6a in Pennsylvania

598 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 121

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 207

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 170

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 9

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 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Milan, PA.

Soil in Milan, PA

The soil mapped at the center of ZIP 18831 is Oquaga — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
pH4.8strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter80%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Oquaga channery silt loam, 3 to 8 percent slopes, rubbly.

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 18831; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Milan, PA

Summer high83 °Faverage high, July
Winter low16 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights149nights a year at 32 °F or less
Growing degree days2,609base 50 °F — the season’s usable heat
Longest day15 h 14 mindaylight on June 21
Shortest day9 h 07 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation35.5 inper year, rain and melted snow
Snowfall35 inper year; 55 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 16 °F 34°16° JanFebruary: average high 37 °F, low 17 °F 37°17° FebMarch: average high 45 °F, low 24 °F 45°24° MarApril: average high 59 °F, low 34 °F 59°34° AprMay: average high 71 °F, low 45 °F 71°45° MayJune: average high 79 °F, low 54 °F 79°54° JunJuly: average high 83 °F, low 58 °F 83°58° JulAugust: average high 82 °F, low 57 °F 82°57° AugSeptember: average high 75 °F, low 50 °F 75°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: 1.89 in precipitation, 9.1 in snowfall 1.9❄9 JanFebruary: 1.59 in precipitation, 8.3 in snowfall 1.6❄8 FebMarch: 2.45 in precipitation, 7.9 in snowfall 2.5❄8 MarApril: 3.23 in precipitation, 1.5 in snowfall 3.2❄2 AprMay: 3.07 in precipitation 3.1 MayJune: 4.09 in precipitation 4.1 JunJuly: 3.60 in precipitation 3.6 JulAugust: 3.57 in precipitation 3.6 AugSeptember: 3.89 in precipitation 3.9 SepOctober: 3.52 in precipitation, 0.1 in snowfall 3.5 OctNovember: 2.26 in precipitation, 1.7 in snowfall 2.3❄2 NovDecember: 2.33 in precipitation, 6.4 in snowfall 2.3❄6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Waverly, NY (8 mi away); precipitation: Chemung, NY (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

188176a
East Smithfield, PA · 2 mi
188106a
Athens, PA · 6 mi
188406a
Sayre, PA · 6 mi
188506a
Ulster, PA · 7 mi
188146a
Burlington, PA · 8 mi
169146a
Columbia Cross Roads, PA · 10 mi
169256a
Gillett, PA · 10 mi
148926a
Waverly, NY · 11 mi

Pennsylvania planting zones →

Questions about 18831

What planting zone is ZIP code 18831?

ZIP code 18831 (Milan, PA) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Milan, PA?

The median last spring frost (32 °F) near 18831 is May 6; after May 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Waverly station.

When is the first frost in Milan, PA?

The median first fall frost near 18831 is October 10, giving a median frost-free growing season of 157 days.

When should I plant tomatoes in 18831?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 18831 get?

About 35.5 inches of precipitation a year and 35 inches of snowfall (NOAA 1991–2020 normals, Chemung station).

How hot do summers get in Milan, PA?

The average high peaks at 83 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 18831 have?

The USDA soil survey maps Oquaga at the center of ZIP 18831: moderately decomposed plant material, well drained, pH about 4.8 (strongly acidic).

Did spring come early in Milan, PA in 2026?

Spring leaf-out near 18831 came on Apr 6 in 2026, 6 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Milan, PA?

Long-day onions: the longest day near 18831 is 15 h 14 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 18831 change?

Yes. The 2012 USDA map put 18831 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.