Bethlehem, PA 18018 Frost Dates
Bethlehem, PA: when does the frost end?
The last spring frost here typically falls around 04/20, about 235 days from today. Fall's first freeze usually shows up around 10/24, roughly 184 days after the last spring frost.
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 Bethlehem, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Bethlehem's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
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.
Bethlehem against the rest of the dataset
At roughly 184 frost-free days, Bethlehem places 23,399 of 40,283 ZIP codes in this dataset. Within PA, it ranks 756 of 2,088.
Learn more
Before leaning on 18018's figures: the frost range explains how to read the range around Bethlehem's dates instead of trusting one, while local microclimates explains what one yard in Bethlehem can differ from the 18018 normal.