Frost Dates for 17304 — Aspers, Pennsylvania

Half of springs at Biglerville, PA see their last 32°F night by April 15; only one in ten is past it by April 1, and one in ten still has one after May 4. Planting tender crops after April 22 leaves a 30% risk of a frost on them, after April 29 20%, and after May 4 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 27 in half of years, as early as October 11 one year in ten, and holds off past November 10 one year in ten. A hard freeze of 28°F follows 12 days later, around November 8; in spring the one-in-ten date for 28°F is April 17, 17 days before the 32°F one. The freeze-free season lasts 194 days in a typical year, longer than at 86% of the 176 Pennsylvania stations; it reaches 215 days one year in ten and falls short of 172 one year in ten. On average 115 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 15 days longer, to about April 30, and return around October 15. Severe cold of 16°F or below comes every winter, usually between December 19 and March 5.

July is the warmest month at Biglerville, PA, averaging 86°F by day and 65°F at night; January is the coldest at 38°F and 22°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 16% of years.

Warmth for growing adds up to 3,368 growing degree days a year (base 50°F), more than at 84% of the 176 Pennsylvania stations. 34% of them (1,142) have built up by the end of June, and July adds the most, 781. Precipitation totals 45.2 inches a year, most in September (5.2") and least in February (2.6"); May to September bring 47% of it.

The nearest other station, Cashtown 1S, PA, 9 miles southwest of Aspers, has a last frost 13 days later (April 28), a first frost 10 days earlier (October 17), a season 24 days shorter.

The first measurable snow (0.1 inch or more) in Aspers usually arrives around December 11, and the last of the season around March 19. Those are the middle dates across the winters of 1991–2020 at Biglerville, PA, 3.1 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 27 days after the last snow.

ZIP 17304 is 3 miles from Biglerville, PA, which stands at 720 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 17307 (Biglerville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 17304 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.