Frost Dates for 17842 — Middleburg, Pennsylvania

Half of springs at Selinsgrove Penn Vly Airport, PA see their last 32°F night by April 27; only one in ten is past it by April 13, and one in ten still has one after May 12. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 7 20%, and after May 12 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 72% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 3 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 13 days later, around October 29; in spring the one-in-ten date for 28°F is April 29, 13 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, shorter than at 55% of the 176 Pennsylvania stations; it reaches 192 days one year in ten and falls short of 151 one year in ten. On average 128 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 10 days longer, to about May 7, and return around October 5. Severe cold of 16°F or below comes every winter, usually between December 6 and March 9.

July is the warmest month at Selinsgrove Penn Vly Airport, PA, averaging 84°F by day and 62°F at night; January is the coldest at 36°F and 20°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 36% of years.

Warmth for growing adds up to 3,006 growing degree days a year (base 50°F), more than at 52% of the 176 Pennsylvania stations. 35% of them (1,046) have built up by the end of June, and July adds the most, 722. Precipitation totals 41.1 inches a year, most in September (4.5") and least in February (2.1"); May to September bring 48% of it.

The nearest other station, Selinsgrove 2 S, PA, 9 miles east of Middleburg, has a last frost 2 days earlier (April 25), a first frost 6 days later (October 22), a season 6 days longer.

The first measurable snow (0.1 inch or more) in Middleburg usually arrives around December 6, and the last of the season around March 17. Those are the middle dates across the winters of 1991–2020 at Beavertown 1 NE, PA, 6.5 miles away: half of years saw snow earlier, half later. Snow fell in 94% of those winters. The last 32°F night of spring typically comes 41 days after the last snow.

ZIP 17842 is 9 miles from Selinsgrove Penn Vly Airport, PA, which stands at 444 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 17870 (Selinsgrove). The 2023 USDA Plant Hardiness Zone Map lists ZIP 17842 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.