St. Marys, PA 15868 Frost Dates
St. Marys, PA: when does the frost end?
Typically, the last spring freeze lands around 05/04, roughly 249 days out. Fall's first freeze usually shows up around 10/11, roughly 161 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts St. Marys in Zone 6a (-10 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
With roughly 6 weeks until St. Marys's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around St. Marys's last frost
05/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/22 and only about 1 year in 10 sees frost after that.
St. Marys against the rest of the dataset
About 161 days separate St. Marys's last and first frost, putting it 31,994 of 40,283 ZIP codes nationally. Within PA, it ranks 1,668 of 2,088.
Learn more
Before leaning on 15868's figures: zone vs. frost date explains why Zone 6a and St. Marys's frost date answer different questions, while the frost range explains how to read the range around St. Marys's dates instead of trusting one.