Lancaster, PA 17603 Frost Dates
17603, near Lancaster, PA: the frost window
The last spring frost here typically falls around 04/18, about 233 days from today. Fall's first freeze usually shows up around 10/25, roughly 186 days after the last spring frost.
Zone 7a (0 to 5°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 Lancaster, not a forecast for this year.
Stretching the season past the first frost
Lancaster's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
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
About 186 days separate Lancaster's last and first frost, putting it 22,695 of 40,283 ZIP codes nationally. Within PA, it ranks 633 of 2,088.
Learn more
Two guides worth reading on 17603: the frost range, on how to read the range around Lancaster's dates instead of trusting one, and local microclimates, on what one yard in Lancaster can differ from the 17603 normal.