Philadelphia, PA 19120 Frost Dates
Philadelphia, PA: when does the frost end?
Around 04/04 is the usual last spring frost, about 219 days away. Fall's first freeze usually shows up around 11/07, roughly 216 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 10 weeks until Philadelphia's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Philadelphia's last frost
04/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/21 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/17 and only about 1 year in 10 sees frost after that.
Philadelphia against the rest of the dataset
About 216 days separate Philadelphia's last and first frost, putting it 13,661 of 40,283 ZIP codes nationally. Within PA, it ranks 57 of 2,088.
Learn more
Before leaning on 19120's figures: the frost range explains how to read the range around Philadelphia's dates instead of trusting one, while local microclimates explains what one yard in Philadelphia can differ from the 19120 normal.