Williamsport, PA 17769 Frost Dates
Frost dates for Williamsport, PA, ZIP 17769
Typically, the last spring freeze lands around 04/24, roughly 239 days out. The first fall frost typically arrives around 10/23, about 180 frost-free days later.
The USDA Plant Hardiness Zone Map puts Williamsport in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 6a around Williamsport 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.
How much risk comes with planting early here
04/24 is the middle of 30 years of NOAA records, not a promise. Plant by 04/12 and you're betting against frost in roughly 9 years out of 10. 05/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Williamsport compares
Williamsport's growing season runs about 180 days, ranking 24,793 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 847 of 2,088.
Learn more
the frost range explains how to read the range around Williamsport's dates instead of trusting one, and local microclimates explains what one yard in Williamsport can differ from the 17769 normal.