Philadelphia, PA 19105 Frost Dates
Frost dates for Philadelphia, PA, ZIP 19105
Typically, the last spring freeze lands around 04/15, roughly 230 days out. The first fall frost typically arrives around 10/31, about 199 frost-free days later.
Zone 7b (5 to 10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Philadelphia, not a forecast for this year.
What to do before the first frost
Zone 7b around Philadelphia has about 9 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 04/15 isn't a guarantee
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
At roughly 199 frost-free days, Philadelphia places 17,933 of 40,283 ZIP codes in this dataset. Within PA, it ranks 246 of 2,088.
Learn more
zone vs. frost date explains why Zone 7b and Philadelphia's frost date answer different questions, and the frost range explains how to read the range around Philadelphia's dates instead of trusting one.