When is the last frost in Philadelphia, PA?

The average (50% probability) last spring frost in Philadelphia is April 2, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until April 13.

When is the first frost in Philadelphia?

The average first fall frost in Philadelphia is November 10, with a growing season of about 224 days.

Home › States › Philadelphia

Philadelphia, Pennsylvania frost dates

Average last spring frost: April 2. Average first fall frost: November 10. That gives a growing season of about 224 days. For frost-tender plants, a safer planting date is April 13, after which a freeze happens in only 1 year in 10.

Last frost (50%)

Apr 2

1-in-10 risk after Apr 13

First frost (50%)

Nov 10

1-in-10 risk before Oct 30

Growing season

224 days

median frost-free days

Hard freeze (28°F)

Mar 22

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	March 19	November 24
70%	March 29	November 16
50%	April 2	November 10
30%	April 6	November 5
10%	April 13	October 30

Read the spring column like this: there is a 10% chance of a 32°F freeze after April 13. These are NOAA probabilities for the Philadelphia International Airport weather station (USW00013739, elevation 3 m), 1991–2020.

Philadelphia vegetable planting calendar

Dates count from the 50% last-frost date (April 2). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (Apr 13) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Mar 12	Apr 9 (usually sown directly in the garden)
Broccoli	Jan 22	Mar 5
Brussels sprouts	Jan 22	Mar 5
Cabbage	Jan 15	Feb 26
Cauliflower	Feb 5	Mar 19
Sweet corn	Mar 5	Apr 2 (usually sown directly in the garden)
Cucumbers	Mar 19	Apr 9
Kale	Jan 15	Feb 26
Leeks	Dec 18	Feb 26
Lettuce	Feb 12	Mar 19
Melons	Mar 26	Apr 16
Onions	Dec 11	Feb 19 (from seed; sets and transplants go out at the same time)
Peas	Feb 5	Mar 5 (usually sown directly in the garden)
Peppers	Feb 19	Apr 16
Squash	Mar 26	Apr 16
Tomatoes	Feb 5	Apr 2

Offsets from Oregon State University Extension's seed-starting table. "Plant out" means transplant, or sow directly for crops usually grown from seed.

Fall frost and season extension

The first fall freeze usually arrives around November 10. There's a 1-in-10 chance it comes before October 30. Harvest tender crops such as basil, tomatoes, peppers and squash before then, or cover them on cold nights. Cool-season crops like kale, cabbage and Brussels sprouts handle light frost, and often taste sweeter after it. A hard freeze (28°F) typically comes around November 23.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Allentown, PA	Apr 20	Oct 24	~89 km
Newark, NJ	Apr 2	Nov 10	~128 km
Harrisburg, PA	Apr 9	Nov 2	~135 km
Baltimore, MD	Apr 10	Oct 31	~146 km
New York, NY	Apr 2	Nov 14	~152 km
Washington, DC	Mar 24	Nov 18	~191 km

More: all Pennsylvania frost dates