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

Planting zone for 19318 — Chatham, PA

ZIP code 19318 (Chatham, Chester County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 19 and the first fall frost October 26.

Where ZIP 19318 is

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 19

First frostOct 26

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 Chatham, 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 Chatham, PA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 19median — 50% chance of a later frost

Safe for tender plantsMay 3only 10% chance of frost after

First fall frostOctober 26median — 10% chance by Oct 11

Growing season189 daysfrost-free, median

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

From the NOAA station Avondale 2 N, PA — within 1 mile, elevation 400 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 19318

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 8 – Mar 22

SpinachSow outdoors · Mar 8 – Mar 29

Broccoli, cabbageStart indoors · Feb 8 – Feb 22

Broccoli, cabbageTransplant · Mar 29 – Apr 12

Onion setsPlant outdoors · Mar 22 – Apr 5

PotatoesPlant outdoors · Mar 29 – Apr 12

LettuceSow outdoors · Mar 22 – Apr 5

Carrots, beetsSow outdoors · Mar 29 – Apr 12

TomatoesStart indoors · Feb 22 – Mar 8

TomatoesTransplant · Apr 26 – May 10

Peppers, eggplantStart indoors · Feb 8 – Feb 22

Peppers, eggplantTransplant · May 3 – May 17

BeansSow outdoors · Apr 26 – May 10

Sweet cornSow outdoors · Apr 26 – May 10

Cucumbers, squashSow outdoors · Apr 26 – May 10

Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14

GarlicPlant cloves · Oct 12 – Nov 16

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Oct 26) 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 19318 came on Mar 24 — about the same time as the 1991–2020 average (Mar 24).

average
Mar 242026
Mar 24

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.

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 Chatham, PA.

Soil in Chatham, PA

The soil mapped at the center of ZIP 19318 is Gladstone — gravelly loam, well drained.

TextureGravelly loama good balance for most vegetables

pH6.3slightly 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: Gladstone gravelly 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 19318; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Chatham, PA

Summer high84 °Faverage high, July

Winter low23 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights109nights a year at 32 °F or less

Growing degree days3,143base 50 °F — the season’s usable heat

Longest day15 h 00 mindaylight on June 21

Shortest day9 h 20 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation47.1 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: Avondale 2 N, PA (within 1 mile); precipitation: Avondale 2 N, PA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

193907a

West Grove, PA · 2 mi

193117a

Avondale, PA · 3 mi

193747a

Toughkenamon, PA · 4 mi

193467a

Kelton, PA · 5 mi

193487a

Kennett Square, PA · 5 mi

193757a

Unionville, PA · 5 mi

193307a

Cochranville, PA · 6 mi

193527a

Lincoln University, PA · 6 mi

Pennsylvania planting zones →

Questions about 19318

What planting zone is ZIP code 19318?

ZIP code 19318 (Chatham, 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 Chatham, PA?

The median last spring frost (32 °F) near 19318 is April 19; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Avondale 2 N station.

When is the first frost in Chatham, PA?

The median first fall frost near 19318 is October 26, giving a median frost-free growing season of 189 days.

When should I plant tomatoes in 19318?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 19318 get?

About 47.1 inches of precipitation a year (NOAA 1991–2020 normals, Avondale 2 N station).

How hot do summers get in Chatham, PA?

The average high peaks at 84 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 19318 have?

The USDA soil survey maps Gladstone at the center of ZIP 19318: gravelly loam, well drained, pH about 6.3 (slightly acidic).

Did spring come early in Chatham, PA in 2026?

Spring leaf-out near 19318 came on Mar 24 in 2026, about the same as the 1991–2020 average (Mar 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Chatham, PA?

Intermediate onions: the longest day near 19318 is 15 h 00 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 19318 change?

Yes. The 2012 USDA map put 19318 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.