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

Planting zone for 18032 — Catasauqua, PA

ZIP code 18032 (Catasauqua, Lehigh 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 24.

Where ZIP 18032 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 24

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 Catasauqua, 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 Catasauqua, 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 6only 10% chance of frost after

First fall frostOctober 24median — 10% chance by Oct 8

Growing season184 daysfrost-free, median

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

From the NOAA station Allentown Intl Airport, PA — within 1 mile, elevation 390 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 18032

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 29 – Sep 12

GarlicPlant cloves · Oct 10 – Nov 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 24) 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 18032 came on Mar 26 — 4 days earlier than the 1991–2020 average (Mar 30).

average
Mar 302026
Mar 26

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 Catasauqua, PA

The soil mapped at the center of ZIP 18032 is Duffield — silt loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSilt loama good balance for most vegetables

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Duffield complex, 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 18032; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Catasauqua, PA

Summer high86 °Faverage high, July

Winter low22 °Faverage low, January

Hot days18days a year at 90 °F or more

Freezing nights118nights a year at 32 °F or less

Growing degree days3,405base 50 °F — the season’s usable heat

Longest day15 h 05 mindaylight on June 21

Shortest day9 h 15 mindaylight on December 21

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

Precipitation47.4 inper year, rain and melted snow

Snowfall33 inper year; 31 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: Allentown Intl Airport, PA (within 1 mile); precipitation: Allentown Intl Airport, PA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

Lehigh Valley, PA · 2 mi

180017a

Lehigh Valley, PA · 3 mi

180037a

Lehigh Valley, PA · 3 mi

Pennsylvania planting zones →

Questions about 18032

What planting zone is ZIP code 18032?

ZIP code 18032 (Catasauqua, 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 Catasauqua, PA?

The median last spring frost (32 °F) near 18032 is April 20; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Allentown Intl Airport station.

When is the first frost in Catasauqua, PA?

The median first fall frost near 18032 is October 24, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 18032?

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 18032 get?

About 47.4 inches of precipitation a year and 33 inches of snowfall (NOAA 1991–2020 normals, Allentown Intl Airport station).

How hot do summers get in Catasauqua, PA?

The average high peaks at 86 °F in July, with about 18 days a year at 90 °F or more.

What kind of soil does 18032 have?

The USDA soil survey maps Duffield at the center of ZIP 18032: silt loam, well drained, pH about 6.7 (neutral).

Did spring come early in Catasauqua, PA in 2026?

Spring leaf-out near 18032 came on Mar 26 in 2026, 4 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Catasauqua, PA?

Long-day onions: the longest day near 18032 is 15 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 18032 change?

Yes. The 2012 USDA map put 18032 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.