Philadelphia, PA 19193 Frost Dates
19193, near Philadelphia, PA: the frost window
Typically, the last spring freeze lands around 04/15, roughly 230 days out. Fall's first freeze usually shows up around 10/31, roughly 199 days after the last spring frost.
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.
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.
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
Philadelphia's growing season runs about 199 days, ranking 17,962 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 275 of 2,088.
Learn more
Two guides worth reading on 19193: the frost range, on how to read the range around Philadelphia's dates instead of trusting one, and local microclimates, on what one yard in Philadelphia can differ from the 19193 normal.