Philadelphia, PA 19160 Frost Dates
Philadelphia, PA: when does the frost end?
The last spring frost here typically falls around 04/15, about 230 days from today. Fall's first freeze usually shows up around 10/31, roughly 199 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 9 weeks until Philadelphia's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/15 isn't a guarantee
04/15 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/01 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/01 and only about 1 year in 10 sees frost after that.
Philadelphia against the rest of the dataset
About 199 days separate Philadelphia's last and first frost, putting it 17,944 of 40,283 ZIP codes nationally. Within PA, it ranks 257 of 2,088.
Learn more
Before leaning on 19160's figures: zone vs. frost date explains why Zone 7b and Philadelphia's frost date answer different questions, while the frost range explains how to read the range around Philadelphia's dates instead of trusting one.