Frost Dates for 16738 — Lewis Run, Pennsylvania

Half of springs at Bradford Regional Airport, PA see their last 32°F night by May 18; only one in ten is past it by April 30, and one in ten still has one after May 31. Planting tender crops after May 24 leaves a 30% risk of a frost on them, after May 27 20%, and after May 31 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 94% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 18 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 13 days later, around October 14; in spring the one-in-ten date for 28°F is May 21, 10 days before the 32°F one. The freeze-free season lasts 136 days in a typical year, shorter than at 97% of the 176 Pennsylvania stations; it reaches 158 days one year in ten and falls short of 115 one year in ten. On average 160 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 14 days longer, to about June 1, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 24 and March 28.

July is the warmest month at Bradford Regional Airport, PA, averaging 79°F by day and 55°F at night; January is the coldest at 31°F and 16°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 86% of years.

Warmth for growing adds up to 2,065 growing degree days a year (base 50°F), fewer than at 95% of the 176 Pennsylvania stations. 33% of them (680) have built up by the end of June, and July adds the most, 522. Precipitation totals 42.0 inches a year, most in May (4.2") and least in February (2.1"); May to September bring 48% of it.

The nearest other station, Bradford 4SW Rsch 5, PA, 5 miles north of Lewis Run and 457 feet lower, has the same 50% last-frost date, a first frost 3 days later (October 4), a season 4 days longer.

The first measurable snow (0.1 inch or more) in Lewis Run usually arrives around November 8, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Bradford 4SW Rsch 5, PA, 4.6 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 43 days after the last snow.

ZIP 16738 is 3 miles from Bradford Regional Airport, PA, which stands at 2,117 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16738 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.