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When to plant in Philadelphia, PA

USDA Zone 7b

Here are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Philadelphia, Pennsylvania — all computed from Philadelphia's nearest NOAA weather station.

In zone 7b, Philadelphia supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.

Station · PHILA FRANKLIN INST · 6.6 km
Last spring frost
March 30
50% chance · 32°F
First fall frost
November 17
50% chance · 32°F
Growing season
232 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for PhiladelphiaA year-band showing 32°F frost risk from January to December for Philadelphia: last spring frost around March 30, first fall frost around November 17, about 232 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

Frost probability

PHILA FRANKLIN INST · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Philadelphia’s own odds, recorded at PHILA FRANKLIN INST.

Frost-probability curves for PhiladelphiaProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around March 30 and the first fall frost around November 17, giving about 232 frost-free days.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FApr 23Apr 8Mar 27Oct 23Nov 5Nov 20
32°FApr 12Mar 30Mar 15Nov 4Nov 17Dec 4
28°FMar 31Mar 17Mar 1Nov 12Nov 29Dec 18

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19
Fall sowin 9 days
Brussels Sprouts
July 28August 11
Fall sowin 23 days
Rutabaga
August 11August 25

Add these crops to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Philadelphia, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 13 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

PHILA FRANKLIN INST
Primary
7 km · 18 m elevation
SPRING
Mar 30
FALL
Nov 17
PENNSAUKEN 1N
11 km · 14 m elevation
SPRING
Apr 15
FALL
Oct 31
PHILADELPHIA NE AP
13 km · 31 m elevation
SPRING
Apr 4
FALL
Nov 7

Philadelphia planting FAQ

When is the last spring frost in Philadelphia, PA?

Plan for the last spring frost in Philadelphia around March 30 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.

When is the first fall frost in Philadelphia, PA?

In Philadelphia, the first 32°F freeze of fall lands around November 17 on average. Time your last harvests and any season-extension cover before it.

What hardiness zone is Philadelphia in?

Philadelphia is in USDA hardiness zone 7b. In zone 7b, winters are moderate — most common vegetables grow well in season.

How long is the growing season in Philadelphia?

Philadelphia has about 232 frost-free days — a long growing season — between the average last spring frost (March 30) and first fall frost (November 17).

When should I plant tomatoes in Philadelphia?

For Philadelphia, sow tomatoes indoors about February 2–February 16 and move the seedlings out around April 6, after the last spring frost.

Planting reminders

Never miss a window in Philadelphia

An email when it’s time to start seeds, transplant, and sow — timed to Philadelphia’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at PHILA FRANKLIN INST, 7 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Philadelphia, PA — Frost Dates & Zone 7b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00366886. Retrieved from https://blissgarden.com/pennsylvania/philadelphia.