Philadelphia, PA 19122 Frost Dates
19122, near Philadelphia, PA: the frost window
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
Philadelphia's growing season runs out in roughly 9 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Philadelphia's last frost
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
At roughly 199 frost-free days, Philadelphia places 17,935 of 40,283 ZIP codes in this dataset. Within PA, it ranks 248 of 2,088.
Learn more
Two guides worth reading on 19122: local microclimates, on what one yard in Philadelphia can differ from the 19122 normal, and zone vs. frost date, on why Zone 7b and Philadelphia's frost date answer different questions.