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

Planting zone for Mechanicsburg, PA

Mechanicsburg, PA is in USDA zone 7a across its 2 ZIP codes. The median last spring frost is April 23 and the first fall frost October 18.

Mechanicsburg on the zone map

Outlined: its 2 ZIP code areas · 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
ZIP codes2
Last frostApr 23
First frostOct 18
Growing season177 days

7a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Mechanicsburg, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 23median — 50% chance of a later frost
Safe for tender plantsMay 9only 10% chance of frost after
First fall frostOctober 18median — 10% chance by Oct 4
Growing season177 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 10 and returns around November 1.

From the NOAA station Carlisle Wtp, PA, elevation 430 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 Mechanicsburg

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 12 – Mar 26
SpinachSow outdoors · Mar 12 – Apr 2
Broccoli, cabbageStart indoors · Feb 12 – Feb 26
Broccoli, cabbageTransplant · Apr 2 – Apr 16
Onion setsPlant outdoors · Mar 26 – Apr 9
PotatoesPlant outdoors · Apr 2 – Apr 16
LettuceSow outdoors · Mar 26 – Apr 9
Carrots, beetsSow outdoors · Apr 2 – Apr 16
TomatoesStart indoors · Feb 26 – Mar 12
TomatoesTransplant · Apr 30 – May 14
Peppers, eggplantStart indoors · Feb 12 – Feb 26
Peppers, eggplantTransplant · May 7 – May 21
BeansSow outdoors · Apr 30 – May 14
Sweet cornSow outdoors · Apr 30 – May 14
Cucumbers, squashSow outdoors · Apr 30 – May 14
Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6
GarlicPlant cloves · Oct 4 – Nov 8
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 18) 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 17050 came on Mar 21 — 7 days earlier than the 1991–2020 average (Mar 28).

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 Mechanicsburg, PA.

Soil in Mechanicsburg, PA

The soil mapped at the center of ZIP 17050 is Hagerstown — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Hagerstown 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 17050; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mechanicsburg, PA

Summer high86 °Faverage high, July
Winter low21 °Faverage low, January
Hot days24days a year at 90 °F or more
Freezing nights127nights a year at 32 °F or less
Growing degree days3,156base 50 °F — the season’s usable heat
Longest day15 h 02 mindaylight on June 21
Shortest day9 h 18 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation45.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 38 °F, low 21 °F 38°21° JanFebruary: average high 41 °F, low 22 °F 41°22° FebMarch: average high 50 °F, low 29 °F 50°29° MarApril: average high 63 °F, low 39 °F 63°39° AprMay: average high 73 °F, low 49 °F 73°49° MayJune: average high 81 °F, low 59 °F 81°59° JunJuly: average high 86 °F, low 63 °F 86°63° JulAugust: average high 84 °F, low 61 °F 84°61° AugSeptember: average high 77 °F, low 53 °F 77°53° SepOctober: average high 66 °F, low 42 °F 66°42° OctNovember: average high 54 °F, low 32 °F 54°32° NovDecember: average high 42 °F, low 25 °F 42°25° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.07 in precipitation 3.1 JanFebruary: 2.72 in precipitation 2.7 FebMarch: 3.73 in precipitation 3.7 MarApril: 3.65 in precipitation 3.6 AprMay: 4.00 in precipitation 4.0 MayJune: 4.43 in precipitation 4.4 JunJuly: 4.58 in precipitation 4.6 JulAugust: 3.84 in precipitation 3.8 AugSeptember: 4.90 in precipitation 4.9 SepOctober: 3.84 in precipitation 3.8 OctNovember: 3.16 in precipitation 3.2 NovDecember: 3.69 in precipitation 3.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Carlisle Wtp, PA (9 mi away); precipitation: Mechanicsburg 1.0 Nnw, PA (2 mi away). Daylight is calculated from latitude.

ZIP codes in Mechanicsburg

170507a
0 to 5 °F
170557a
0 to 5 °F

Pennsylvania planting zones →

Questions about Mechanicsburg

What planting zone is Mechanicsburg, PA?

Mechanicsburg, PA is in USDA hardiness zone 7a on the 2023 map (7a: 0 to 5 °F).

When is the last frost in Mechanicsburg, PA?

The median last spring frost is April 23 and the median first fall frost is October 18 (NOAA 1991–2020 normals, Carlisle Wtp station).

When can I plant a garden in Mechanicsburg, PA?

Cool-season crops like peas and spinach go in around Mar 12 – Apr 2; tomatoes, peppers, beans and squash after about Apr 30, once frost risk has passed.

What kind of onions grow in Mechanicsburg, PA?

Long-day onions: the longest day is 15 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Mechanicsburg, PA get?

About 45.6 inches of precipitation a year (NOAA 1991–2020 normals).