Herndon, PA 17864 Frost Dates
Herndon, PA: when does the frost end?
Around 04/27 is the usual last spring frost, about 242 days away. Fall's first freeze usually shows up around 10/16, roughly 172 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Herndon in Zone 6b (-5 to 0°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 7 weeks until Herndon's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/13 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Herndon against the rest of the dataset
About 172 days separate Herndon's last and first frost, putting it 28,474 of 40,283 ZIP codes nationally. Within PA, it ranks 1,408 of 2,088.
Learn more
Before leaning on 17864's figures: the frost range explains how to read the range around Herndon's dates instead of trusting one, while local microclimates explains what one yard in Herndon can differ from the 17864 normal.