St. Clair, PA 17966 Frost Dates
St. Clair, PA: when does the frost end?
The last spring frost here typically falls around 04/30, about 245 days from today. Fall's first freeze usually shows up around 10/22, roughly 175 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts St. Clair 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
With roughly 8 weeks until St. Clair'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. Clair's last frost
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
St. Clair against the rest of the dataset
St. Clair's growing season runs about 175 days, ranking 26,944 of 40,283 US ZIP codes measured here, longest to shortest. Within PA, it ranks 1,164 of 2,088.
Learn more
Before leaning on 17966's figures: local microclimates explains what one yard in St. Clair can differ from the 17966 normal, while zone vs. frost date explains why Zone 7a and St. Clair's frost date answer different questions.