Frost Dates for 16342 — Polk, Pennsylvania

Half of springs at Franklin, PA see their last 32°F night by May 2; only one in ten is past it by April 20, and one in ten still has one after May 20. Planting tender crops after May 9 leaves a 30% risk of a frost on them, after May 15 20%, and after May 20 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 70% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 23 in half of years, as early as October 8 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 11 days later, around November 3; in spring the one-in-ten date for 28°F is May 8, 12 days before the 32°F one. The freeze-free season lasts 171 days in a typical year, shorter than at 57% of the 176 Pennsylvania stations; it reaches 190 days one year in ten and falls short of 153 one year in ten. On average 142 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 13, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 7 and March 17.

July is the warmest month at Franklin, PA, averaging 83°F by day and 60°F at night; January is the coldest at 34°F and 18°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 55% of years.

Warmth for growing adds up to 2,697 growing degree days a year (base 50°F), fewer than at 66% of the 176 Pennsylvania stations. 33% of them (898) have built up by the end of June, and July adds the most, 656. Precipitation totals 46.5 inches a year, most in July (5.3") and least in February (2.7"); May to September bring 48% of it.

The nearest other station, Mercer, PA, 17 miles southwest of Polk and 205 feet higher, has a last frost 13 days later (May 15), a first frost 20 days earlier (October 3), a season 31 days shorter.

The first measurable snow (0.1 inch or more) in Polk usually arrives around November 24, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Franklin, PA, 7.1 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 37 days after the last snow.

ZIP 16342 is 7 miles from Franklin, PA, which stands at 1,015 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 16301 (Oil City). The 2023 USDA Plant Hardiness Zone Map lists ZIP 16342 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.