Jefferson, PA 17311 Frost Dates
Frost dates for Jefferson, PA, ZIP 17311
Around 04/19 is the usual last spring frost, about 234 days away. The first fall frost typically arrives around 10/25, about 188 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 Jefferson, not a forecast for this year.
What to do before the first frost
Zone 7a around Jefferson 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 Jefferson's last frost
04/19 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. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Jefferson compares
About 188 days separate Jefferson's last and first frost, putting it 22,141 of 40,283 ZIP codes nationally. Within PA, it ranks 594 of 2,088.
Learn more
the frost range explains how to read the range around Jefferson's dates instead of trusting one, and local microclimates explains what one yard in Jefferson can differ from the 17311 normal.