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

Planting zone for Philadelphia, PA

Philadelphia, PA is in USDA zone 7b across its 87 ZIP codes. The median last spring frost is March 30 and the first fall frost November 17.

Philadelphia on the zone map

Outlined: its 50 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.

Zone7b5 to 10 °F

ZIP codes87

Last frostMar 30

First frostNov 17

Growing season232 days

7b 87 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Philadelphia, 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 Philadelphia, PA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 30median — 50% chance of a later frost

Safe for tender plantsApril 12only 10% chance of frost after

First fall frostNovember 17median — 10% chance by Nov 4

Growing season232 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 17 and returns around November 29.

From the NOAA station Phila Franklin Inst, PA, elevation 59 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 Philadelphia

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 16 – Mar 2

SpinachSow outdoors · Feb 16 – Mar 9

Broccoli, cabbageStart indoors · Jan 19 – Feb 2

Broccoli, cabbageTransplant · Mar 9 – Mar 23

Onion setsPlant outdoors · Mar 2 – Mar 16

PotatoesPlant outdoors · Mar 9 – Mar 23

LettuceSow outdoors · Mar 2 – Mar 16

Carrots, beetsSow outdoors · Mar 9 – Mar 23

TomatoesStart indoors · Feb 2 – Feb 16

TomatoesTransplant · Apr 6 – Apr 20

Peppers, eggplantStart indoors · Jan 19 – Feb 2

Peppers, eggplantTransplant · Apr 13 – Apr 27

BeansSow outdoors · Apr 6 – Apr 20

Sweet cornSow outdoors · Apr 6 – Apr 20

Cucumbers, squashSow outdoors · Apr 6 – Apr 20

Fall lettuce, spinachSow outdoors · Sep 22 – Oct 6

GarlicPlant cloves · Nov 3 – Dec 8

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 30) and first fall frost (Nov 17) 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 19133 came on Mar 13 — 4 days earlier than the 1991–2020 average (Mar 17).

average
Mar 172026
Mar 13

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 Philadelphia, PA

The center of ZIP 19133 is mapped as Urban land: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 19133; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Philadelphia, PA

Summer high89 °Faverage high, July

Winter low28 °Faverage low, January

Hot days40days a year at 90 °F or more

Freezing nights62nights a year at 32 °F or less

Growing degree days4,429base 50 °F — the season’s usable heat

Longest day15 h 01 mindaylight on June 21

Shortest day9 h 20 mindaylight on December 21

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

Precipitation50.7 inper year, rain and melted snow

Snowfall16 inper year; 15 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: Phila Franklin Inst, PA (3 mi away); precipitation: Phila Franklin Inst, PA (3 mi away). Daylight is calculated from latitude.