Philadelphia, PA 19178 Frost Dates
Frost dates for Philadelphia, PA, ZIP 19178
The last spring frost here typically falls around 04/15, about 230 days from today. 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.
The actual range around Philadelphia's last frost
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 17,952 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 265 of 2,088.
Learn more
local microclimates explains what one yard in Philadelphia can differ from the 19178 normal, and zone vs. frost date explains why Zone 7b and Philadelphia's frost date answer different questions.