Lancaster, PA 17604 Frost Dates
Frost dates for Lancaster, PA, ZIP 17604
The last spring frost here typically falls around 04/18, about 233 days from today. The first fall frost typically arrives around 10/25, about 186 frost-free days later.
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.
What to do before the first frost
Zone 7a around Lancaster has about 8 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around Lancaster's last frost
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 04/04 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Lancaster compares
Lancaster's growing season runs about 186 days, ranking 22,696 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 634 of 2,088.
Learn more
zone vs. frost date explains why Zone 7a and Lancaster's frost date answer different questions, and the frost range explains how to read the range around Lancaster's dates instead of trusting one.