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

Planting zone for 17064 — Mount Gretna, PA

ZIP code 17064 (Mount Gretna, Lebanon County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 20 and the first fall frost October 25.

Where ZIP 17064 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 20

First frostOct 25

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 Mount Gretna, 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 Mount Gretna, PA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 20median — 50% chance of a later frost

Safe for tender plantsMay 7only 10% chance of frost after

First fall frostOctober 25median — 10% chance by Oct 10

Growing season185 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 5.

From the NOAA station Lebanon 2 W, PA — 6 miles away, elevation 449 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 17064

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 9 – Mar 23

SpinachSow outdoors · Mar 9 – Mar 30

Broccoli, cabbageStart indoors · Feb 9 – Feb 23

Broccoli, cabbageTransplant · Mar 30 – Apr 13

Onion setsPlant outdoors · Mar 23 – Apr 6

PotatoesPlant outdoors · Mar 30 – Apr 13

LettuceSow outdoors · Mar 23 – Apr 6

Carrots, beetsSow outdoors · Mar 30 – Apr 13

TomatoesStart indoors · Feb 23 – Mar 9

TomatoesTransplant · Apr 27 – May 11

Peppers, eggplantStart indoors · Feb 9 – Feb 23

Peppers, eggplantTransplant · May 4 – May 18

BeansSow outdoors · Apr 27 – May 11

Sweet cornSow outdoors · Apr 27 – May 11

Cucumbers, squashSow outdoors · Apr 27 – May 11

Fall lettuce, spinachSow outdoors · Aug 30 – Sep 13

GarlicPlant cloves · Oct 11 – Nov 15

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 25) 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 17064 came on Mar 23 — 7 days earlier than the 1991–2020 average (Mar 30).

average
Mar 302026
Mar 23

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 Mount Gretna, PA

The soil mapped at the center of ZIP 17064 is Ungers — loam, well drained.

TextureLoama good balance for most vegetables

pH5.4strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Ungers loam, 8 to 15 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 17064; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mount Gretna, PA

Summer high84 °Faverage high, July

Winter low22 °Faverage low, January

Hot days13days a year at 90 °F or more

Freezing nights120nights a year at 32 °F or less

Growing degree days3,214base 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)

Precipitation46.4 inper year, rain and melted snow

Snowfall24 inper year; 26 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lebanon 2 W, PA (6 mi away); precipitation: Lebanon 2 W, PA (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

Campbelltown, PA · 6 mi

170787a

Palmyra, PA · 6 mi

Pennsylvania planting zones →

Questions about 17064

What planting zone is ZIP code 17064?

ZIP code 17064 (Mount Gretna, 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 Mount Gretna, PA?

The median last spring frost (32 °F) near 17064 is April 20; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lebanon 2 W station.

When is the first frost in Mount Gretna, PA?

The median first fall frost near 17064 is October 25, giving a median frost-free growing season of 185 days.

When should I plant tomatoes in 17064?

Start tomato seeds indoors around Feb 23 – Mar 9 and set transplants outside around Apr 27 – May 11, one to three weeks after the median last frost.

How much rain and snow does 17064 get?

About 46.4 inches of precipitation a year and 24 inches of snowfall (NOAA 1991–2020 normals, Lebanon 2 W station).

How hot do summers get in Mount Gretna, PA?

The average high peaks at 84 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 17064 have?

The USDA soil survey maps Ungers at the center of ZIP 17064: loam, well drained, pH about 5.4 (strongly acidic).

Did spring come early in Mount Gretna, PA in 2026?

Spring leaf-out near 17064 came on Mar 23 in 2026, 7 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mount Gretna, PA?

Long-day onions: the longest day near 17064 is 15 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 17064 change?

Yes. The 2012 USDA map put 17064 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.