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

Planting zone for 16854 — Millheim, PA

ZIP code 16854 (Millheim, Centre County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 5 and the first fall frost October 6.

Where ZIP 16854 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 5
First frostOct 6
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 Millheim, 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 Millheim, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 5median — 50% chance of a later frost
Safe for tender plantsMay 24only 10% chance of frost after
First fall frostOctober 6median — 10% chance by Sep 25
Growing season153 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 24 and returns around October 18.

From the NOAA station Millheim, PA — within 1 mile, elevation 1,119 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 16854

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 24 – Apr 7
SpinachSow outdoors · Mar 24 – Apr 14
Broccoli, cabbageStart indoors · Feb 24 – Mar 10
Broccoli, cabbageTransplant · Apr 14 – Apr 28
Onion setsPlant outdoors · Apr 7 – Apr 21
PotatoesPlant outdoors · Apr 14 – Apr 28
LettuceSow outdoors · Apr 7 – Apr 21
Carrots, beetsSow outdoors · Apr 14 – Apr 28
TomatoesStart indoors · Mar 10 – Mar 24
TomatoesTransplant · May 12 – May 26
Peppers, eggplantStart indoors · Feb 24 – Mar 10
Peppers, eggplantTransplant · May 19 – Jun 2
BeansSow outdoors · May 12 – May 26
Sweet cornSow outdoors · May 12 – May 26
Cucumbers, squashSow outdoors · May 12 – May 26
Fall lettuce, spinachSow outdoors · Aug 11 – Aug 25
GarlicPlant cloves · Sep 22 – Oct 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 5) and first fall frost (Oct 6) 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 16854 came on Mar 31 — 10 days earlier than the 1991–2020 average (Apr 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.

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 Millheim, PA.

Soil in Millheim, PA

The soil mapped at the center of ZIP 16854 is Murrill — 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 matter2.5%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Murrill channery silt loam, 3 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 16854; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Millheim, PA

Summer high84 °Faverage high, July
Winter low15 °Faverage low, January
Hot days11days a year at 90 °F or more
Freezing nights152nights a year at 32 °F or less
Growing degree days2,568base 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)
Precipitation42.4 inper year, rain and melted snow
Snowfall35 inper year; 49 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 15 °F 32°15° JanFebruary: average high 37 °F, low 17 °F 37°17° FebMarch: average high 46 °F, low 25 °F 46°25° MarApril: average high 60 °F, low 35 °F 60°35° AprMay: average high 71 °F, low 45 °F 71°45° MayJune: average high 79 °F, low 55 °F 79°55° JunJuly: average high 84 °F, low 58 °F 84°58° JulAugust: average high 82 °F, low 56 °F 82°56° AugSeptember: average high 74 °F, low 49 °F 74°49° SepOctober: average high 62 °F, low 38 °F 62°38° OctNovember: average high 48 °F, low 29 °F 48°29° NovDecember: average high 38 °F, low 22 °F 38°22° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.96 in precipitation, 9.2 in snowfall 3.0❄9 JanFebruary: 2.32 in precipitation, 8.3 in snowfall 2.3❄8 FebMarch: 3.33 in precipitation, 8.2 in snowfall 3.3❄8 MarApril: 3.63 in precipitation, 1 in snowfall 3.6❄1 AprMay: 3.89 in precipitation 3.9 MayJune: 4.03 in precipitation 4.0 JunJuly: 3.92 in precipitation 3.9 JulAugust: 4.03 in precipitation 4.0 AugSeptember: 4.40 in precipitation 4.4 SepOctober: 3.65 in precipitation, 0.3 in snowfall 3.6 OctNovember: 3.08 in precipitation, 2.2 in snowfall 3.1❄2 NovDecember: 3.20 in precipitation, 6.1 in snowfall 3.2❄6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Millheim, PA (within 1 mile); precipitation: Millheim, PA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

168526b
Madisonburg, PA · 4 mi
168326b
Coburn, PA · 4 mi
168206b
Aaronsburg, PA · 5 mi
168826b
Woodward, PA · 7 mi
168756b
Spring Mills, PA · 7 mi
168726b
Rebersburg, PA · 8 mi
168486b
Lamar, PA · 9 mi
178856b
Weikert, PA · 9 mi

Pennsylvania planting zones →

Questions about 16854

What planting zone is ZIP code 16854?

ZIP code 16854 (Millheim, 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 Millheim, PA?

The median last spring frost (32 °F) near 16854 is May 5; after May 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Millheim station.

When is the first frost in Millheim, PA?

The median first fall frost near 16854 is October 6, giving a median frost-free growing season of 153 days.

When should I plant tomatoes in 16854?

Start tomato seeds indoors around Mar 10 – Mar 24 and set transplants outside around May 12 – May 26, one to three weeks after the median last frost.

How much rain and snow does 16854 get?

About 42.4 inches of precipitation a year and 35 inches of snowfall (NOAA 1991–2020 normals, Millheim station).

How hot do summers get in Millheim, PA?

The average high peaks at 84 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 16854 have?

The USDA soil survey maps Murrill at the center of ZIP 16854: channery silt loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Millheim, PA in 2026?

Spring leaf-out near 16854 came on Mar 31 in 2026, 10 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Millheim, PA?

Long-day onions: the longest day near 16854 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 16854 change?

Yes. The 2012 USDA map put 16854 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.