Macungie, PA 18060 Frost Dates
18060, near Macungie, PA: the frost window
Around 04/20 is the usual last spring frost, about 235 days away. Fall's first freeze usually shows up around 10/24, roughly 184 days after the last spring frost.
Macungie sits in USDA Zone 7a (0 to 5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Macungie'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.
Why 04/20 isn't a guarantee
04/20 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 05/06 and only about 1 year in 10 sees frost after that.
Macungie against the rest of the dataset
About 184 days separate Macungie's last and first frost, putting it 23,538 of 40,283 ZIP codes nationally. Within PA, it ranks 790 of 2,088.
Learn more
Two guides worth reading on 18060: zone vs. frost date, on why Zone 7a and Macungie's frost date answer different questions, and the frost range, on how to read the range around Macungie's dates instead of trusting one.