Frost Dates for 16743 — Port Allegany, Pennsylvania

Half of springs at Port Allegany, PA see their last 32°F night by May 15; only one in ten is past it by April 29, and one in ten still has one after May 29. Planting tender crops after May 22 leaves a 30% risk of a frost on them, after May 25 20%, and after May 29 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 86% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 6 in half of years, as early as September 25 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 14 days later, around October 20; in spring the one-in-ten date for 28°F is May 20, 9 days before the 32°F one. The freeze-free season lasts 144 days in a typical year, shorter than at 90% of the 176 Pennsylvania stations; it reaches 164 days one year in ten and falls short of 125 one year in ten. On average 165 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 13 days longer, to about May 28, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 24 and March 28.

July is the warmest month at Port Allegany, PA, averaging 80°F by day and 56°F at night; January is the coldest at 31°F and 14°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 85% of years.

Warmth for growing adds up to 2,109 growing degree days a year (base 50°F), fewer than at 93% of the 176 Pennsylvania stations. 32% of them (675) have built up by the end of June, and July adds the most, 542. Precipitation totals 42.6 inches a year, most in July (4.5") and least in February (2.3"); May to September bring 48% of it.

The nearest other station, Coudersport 1 SW, PA, 12 miles east of Port Allegany and 175 feet higher, has a last frost 7 days later (May 22), a first frost 5 days earlier (October 1), a season 14 days shorter.

The first measurable snow (0.1 inch or more) in Port Allegany usually arrives around November 13, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Port Allegany, PA, 0.9 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 39 days after the last snow.

ZIP 16743 is under a mile from Port Allegany, PA, which stands at 1,475 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16743 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.