Lancaster, PA 17601 Frost Dates
Lancaster, PA: when does the frost end?
Around 04/18 is the usual last spring frost, about 233 days away. Fall's first freeze usually shows up around 10/25, roughly 186 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Lancaster in Zone 7a (0 to 5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 8 weeks until Lancaster's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/18 isn't a guarantee
04/18 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/04 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/05 and only about 1 year in 10 sees frost after that.
Lancaster against the rest of the dataset
Lancaster's growing season runs about 186 days, ranking 22,693 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 631 of 2,088.
Learn more
Before leaning on 17601's figures: local microclimates explains what one yard in Lancaster can differ from the 17601 normal, while zone vs. frost date explains why Zone 7a and Lancaster's frost date answer different questions.