Knoxville, PA 16928 Frost Dates
Knoxville, PA: when does the frost end?
Typically, the last spring freeze lands around 05/09, roughly 254 days out. Fall's first freeze usually shows up around 10/12, roughly 155 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Knoxville in Zone 5b (-15 to -10°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 6 weeks until Knoxville'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
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/25 and only about 1 year in 10 sees frost after that.
Knoxville against the rest of the dataset
About 155 days separate Knoxville's last and first frost, putting it 34,071 of 40,283 ZIP codes nationally. Within PA, it ranks 1,808 of 2,088.
Learn more
Before leaning on 16928's figures: local microclimates explains what one yard in Knoxville can differ from the 16928 normal, while zone vs. frost date explains why Zone 5b and Knoxville's frost date answer different questions.