Frost Dates for 16101 — New Castle, Pennsylvania

Half of springs at New Castle 1 N, PA see their last 32°F night by April 30; only one in ten is past it by April 17, and one in ten still has one after May 19. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 12 20%, and after May 19 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 90% 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 6 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 10 days later, around November 2; in spring the one-in-ten date for 28°F is May 6, 13 days before the 32°F one. The freeze-free season lasts 175 days in a typical year, shorter than at 48% of the 176 Pennsylvania stations; it reaches 193 days one year in ten and falls short of 153 one year in ten. On average 134 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 11, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 6 and March 15.

July is the warmest month at New Castle 1 N, PA, averaging 86°F by day and 60°F at night; January is the coldest at 37°F and 19°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 48% of years.

Warmth for growing adds up to 3,088 growing degree days a year (base 50°F), more than at 58% of the 176 Pennsylvania stations. 33% of them (1,025) have built up by the end of June, and July adds the most, 718. Precipitation totals 42.0 inches a year, most in July (4.6") and least in February (2.2"); May to September bring 50% of it.

The nearest other station, Slippery Rock 1 SSW, PA, 15 miles east of New Castle and 435 feet higher, has a last frost 7 days later (May 7), a first frost 9 days earlier (October 14), a season 17 days shorter.

The first measurable snow (0.1 inch or more) in New Castle usually arrives around December 4, and the last of the season around March 18. Those are the middle dates across the winters of 1991–2020 at New Castle 1 N, PA, 2.5 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 43 days after the last snow.

ZIP 16101 is 3 miles from New Castle 1 N, PA, which stands at 825 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 11 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16101 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.