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

Planting zone for 17323 — Franklintown, PA

ZIP code 17323 (Franklintown, York County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 9 and the first fall frost November 1.

Where ZIP 17323 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 frostApr 9

First frostNov 1

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 Franklintown, 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 Franklintown, PA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 9median — 50% chance of a later frost

Safe for tender plantsApril 25only 10% chance of frost after

First fall frostNovember 1median — 10% chance by Oct 16

Growing season205 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 12.

From the NOAA station Harrisburg Cptl Cy Airport, PA — 14 miles away, elevation 341 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 17323

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 26 – Mar 12

SpinachSow outdoors · Feb 26 – Mar 19

Broccoli, cabbageStart indoors · Jan 29 – Feb 12

Broccoli, cabbageTransplant · Mar 19 – Apr 2

Onion setsPlant outdoors · Mar 12 – Mar 26

PotatoesPlant outdoors · Mar 19 – Apr 2

LettuceSow outdoors · Mar 12 – Mar 26

Carrots, beetsSow outdoors · Mar 19 – Apr 2

TomatoesStart indoors · Feb 12 – Feb 26

TomatoesTransplant · Apr 16 – Apr 30

Peppers, eggplantStart indoors · Jan 29 – Feb 12

Peppers, eggplantTransplant · Apr 23 – May 7

BeansSow outdoors · Apr 16 – Apr 30

Sweet cornSow outdoors · Apr 16 – Apr 30

Cucumbers, squashSow outdoors · Apr 16 – Apr 30

Fall lettuce, spinachSow outdoors · Sep 6 – Sep 20

GarlicPlant cloves · Oct 18 – Nov 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 9) and first fall frost (Nov 1) 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 17323 came on Mar 21 — 9 days earlier than the 1991–2020 average (Mar 30).

average
Mar 302026
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 Franklintown, PA

The soil mapped at the center of ZIP 17323 is Lehigh — channery silt loam, somewhat poorly drained.

TextureChannery silt loama good balance for most vegetables

pH5.9moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.5%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Lehigh 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 17323; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Franklintown, PA

Summer high88 °Faverage high, July

Winter low25 °Faverage low, January

Hot days26days a year at 90 °F or more

Freezing nights102nights a year at 32 °F or less

Growing degree days3,840base 50 °F — the season’s usable heat

Longest day15 h 01 mindaylight on June 21

Shortest day9 h 19 mindaylight on December 21

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

Precipitation46.6 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Harrisburg Cptl Cy Airport, PA (14 mi away); precipitation: York Springs 0.7 Se, PA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

170197a

Dillsburg, PA · 1 mi

173657a

Wellsville, PA · 5 mi

170277a

Grantham, PA · 6 mi

170077a

Boiling Springs, PA · 7 mi

173727a

York Springs, PA · 7 mi

170557a

Mechanicsburg, PA · 7 mi

173167a

East Berlin, PA · 8 mi

173397a

Lewisberry, PA · 9 mi

Pennsylvania planting zones →

Questions about 17323

What planting zone is ZIP code 17323?

ZIP code 17323 (Franklintown, 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 Franklintown, PA?

The median last spring frost (32 °F) near 17323 is April 9; after April 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Harrisburg Cptl Cy Airport station.

When is the first frost in Franklintown, PA?

The median first fall frost near 17323 is November 1, giving a median frost-free growing season of 205 days.

When should I plant tomatoes in 17323?

Start tomato seeds indoors around Feb 12 – Feb 26 and set transplants outside around Apr 16 – Apr 30, one to three weeks after the median last frost.

How much rain and snow does 17323 get?

About 46.6 inches of precipitation a year (NOAA 1991–2020 normals, York Springs 0.7 Se station).

How hot do summers get in Franklintown, PA?

The average high peaks at 88 °F in July, with about 26 days a year at 90 °F or more.

What kind of soil does 17323 have?

The USDA soil survey maps Lehigh at the center of ZIP 17323: channery silt loam, somewhat poorly drained, pH about 5.9 (moderately acidic).

Did spring come early in Franklintown, PA in 2026?

Spring leaf-out near 17323 came on Mar 21 in 2026, 9 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Franklintown, PA?

Long-day onions: the longest day near 17323 is 15 h 01 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 17323 change?

Yes. The 2012 USDA map put 17323 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.