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

Planting zone for 17018 — Dauphin, PA

ZIP code 17018 (Dauphin, Dauphin County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 1 and the first fall frost October 16.

Where ZIP 17018 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostMay 1
First frostOct 16
2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Dauphin, 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 Dauphin, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 1median — 50% chance of a later frost
Safe for tender plantsMay 20only 10% chance of frost after
First fall frostOctober 16median — 10% chance by Oct 3
Growing season168 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 30.

From the NOAA station Dehart Dam, PA — 5 miles away, elevation 538 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 17018

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 20 – Apr 3
SpinachSow outdoors · Mar 20 – Apr 10
Broccoli, cabbageStart indoors · Feb 20 – Mar 6
Broccoli, cabbageTransplant · Apr 10 – Apr 24
Onion setsPlant outdoors · Apr 3 – Apr 17
PotatoesPlant outdoors · Apr 10 – Apr 24
LettuceSow outdoors · Apr 3 – Apr 17
Carrots, beetsSow outdoors · Apr 10 – Apr 24
TomatoesStart indoors · Mar 6 – Mar 20
TomatoesTransplant · May 8 – May 22
Peppers, eggplantStart indoors · Feb 20 – Mar 6
Peppers, eggplantTransplant · May 15 – May 29
BeansSow outdoors · May 8 – May 22
Sweet cornSow outdoors · May 8 – May 22
Cucumbers, squashSow outdoors · May 8 – May 22
Fall lettuce, spinachSow outdoors · Aug 21 – Sep 4
GarlicPlant cloves · Oct 2 – Nov 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 16) 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 17018 came on Mar 29 — 5 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 7a in Pennsylvania

620 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 78

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 123

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 212

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 181

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 11

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °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 °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 Dauphin, PA.

Soil in Dauphin, PA

The soil mapped at the center of ZIP 17018 is Dekalb — very channery sandy loam, well drained.

TextureVery channery sandy loamdrains and warms fast; dries out and needs more feeding
pH5.1strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Dekalb and Lehew very stony sandy loams, 8 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 17018; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dauphin, PA

Summer high84 °Faverage high, July
Winter low20 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights128nights a year at 32 °F or less
Growing degree days2,845base 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)
Precipitation50.9 inper year, rain and melted snow
Snowfall28 inper year; 36 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 37 °F, low 20 °F 37°20° JanFebruary: average high 40 °F, low 21 °F 40°21° FebMarch: average high 49 °F, low 28 °F 49°28° MarApril: average high 61 °F, low 37 °F 61°37° AprMay: average high 71 °F, low 47 °F 71°47° MayJune: average high 79 °F, low 56 °F 79°56° JunJuly: average high 84 °F, low 60 °F 84°60° JulAugust: average high 82 °F, low 59 °F 82°59° AugSeptember: average high 75 °F, low 52 °F 75°52° SepOctober: average high 64 °F, low 41 °F 64°41° OctNovember: average high 52 °F, low 32 °F 52°32° NovDecember: average high 42 °F, low 25 °F 42°25° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.59 in precipitation, 8.4 in snowfall 3.6❄8 JanFebruary: 2.83 in precipitation, 8.3 in snowfall 2.8❄8 FebMarch: 3.88 in precipitation, 5.1 in snowfall 3.9❄5 MarApril: 4.46 in precipitation, 0.6 in snowfall 4.5❄1 AprMay: 4.42 in precipitation 4.4 MayJune: 4.87 in precipitation 4.9 JunJuly: 5.05 in precipitation 5.0 JulAugust: 4.27 in precipitation 4.3 AugSeptember: 5.63 in precipitation 5.6 SepOctober: 4.54 in precipitation 4.5 OctNovember: 3.30 in precipitation, 0.8 in snowfall 3.3❄1 NovDecember: 4.01 in precipitation, 4.4 in snowfall 4.0❄4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Dehart Dam, PA (5 mi away); precipitation: Dehart Dam, 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.

171127a
Harrisburg, PA · 4 mi
170326b
Halifax, PA · 5 mi
171107a
Harrisburg, PA · 8 mi
171407a
Harrisburg, PA · 8 mi
171087a
Harrisburg, PA · 8 mi
170287a
Grantville, PA · 8 mi
170697a
New Buffalo, PA · 8 mi
171777a
Harrisburg, PA · 9 mi

Pennsylvania planting zones →

Questions about 17018

What planting zone is ZIP code 17018?

ZIP code 17018 (Dauphin, PA) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Dauphin, PA?

The median last spring frost (32 °F) near 17018 is May 1; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Dehart Dam station.

When is the first frost in Dauphin, PA?

The median first fall frost near 17018 is October 16, giving a median frost-free growing season of 168 days.

When should I plant tomatoes in 17018?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 17018 get?

About 50.9 inches of precipitation a year and 28 inches of snowfall (NOAA 1991–2020 normals, Dehart Dam station).

How hot do summers get in Dauphin, PA?

The average high peaks at 84 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 17018 have?

The USDA soil survey maps Dekalb at the center of ZIP 17018: very channery sandy loam, well drained, pH about 5.1 (strongly acidic).

Did spring come early in Dauphin, PA in 2026?

Spring leaf-out near 17018 came on Mar 29 in 2026, 5 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dauphin, PA?

Long-day onions: the longest day near 17018 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 17018 change?

Yes. The 2012 USDA map put 17018 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.