Philadelphia, PA 19129 Frost Dates
When can you plant in Philadelphia, PA?
Around 04/15 is the usual last spring frost, about 230 days away. The first fall frost typically arrives around 10/31, about 199 frost-free days later.
Philadelphia sits in USDA Zone 7b (5 to 10°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 9 weeks of growing season left in Philadelphia before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/15 is the middle of 30 years of NOAA records, not a promise. Plant by 04/01 and you're betting against frost in roughly 9 years out of 10. 05/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Philadelphia compares
Philadelphia's growing season runs about 199 days, ranking 17,938 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 251 of 2,088.
Learn more
zone vs. frost date covers why Zone 7b and Philadelphia's frost date answer different questions. the frost range covers how to read the range around Philadelphia's dates instead of trusting one.