Mifflin, PA 17058 Frost Dates
17058, near Mifflin, PA: the frost window
Typically, the last spring freeze lands around 04/21, roughly 236 days out. Fall's first freeze usually shows up around 10/24, roughly 185 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Mifflin in Zone 7a (0 to 5°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
Mifflin's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Mifflin's last frost
04/21 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/06 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
Mifflin against the rest of the dataset
At roughly 185 frost-free days, Mifflin places 23,286 of 40,283 ZIP codes in this dataset. Within PA, it ranks 728 of 2,088.
Learn more
Two guides worth reading on 17058: local microclimates, on what one yard in Mifflin can differ from the 17058 normal, and zone vs. frost date, on why Zone 7a and Mifflin's frost date answer different questions.