Frost Dates for 15845 — Johnsonburg, Pennsylvania

Half of springs at Glen Hazel 2 NE Dam, PA see their last 32°F night by May 14; only one in ten is past it by April 28, and one in ten still has one after May 29. Planting tender crops after May 21 leaves a 30% risk of a frost on them, after May 24 20%, and after May 29 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 6 in half of years, as early as September 24 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 12 days later, around October 18; in spring the one-in-ten date for 28°F is May 19, 10 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, shorter than at 91% of the 176 Pennsylvania stations; it reaches 163 days one year in ten and falls short of 123 one year in ten. On average 163 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 27, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 25 and March 29.

July is the warmest month at Glen Hazel 2 NE Dam, PA, averaging 79°F by day and 55°F at night; January is the coldest at 31°F and 13°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 84% of years.

Warmth for growing adds up to 2,008 growing degree days a year (base 50°F), fewer than at 97% of the 176 Pennsylvania stations. 32% of them (633) have built up by the end of June, and July adds the most, 519. Precipitation totals 46.7 inches a year, most in July (4.7") and least in February (2.7"); May to September bring 47% of it.

The nearest other station, Ridgway, PA, 6 miles southwest of Johnsonburg and 360 feet lower, has a last frost 1 day earlier (May 13), a first frost 5 days later (October 11), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Johnsonburg usually arrives around November 13, and the last of the season around April 8. Those are the middle dates across the winters of 1991–2020 at Glen Hazel 2 NE Dam, PA, 6.1 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 36 days after the last snow.

ZIP 15845 is 6 miles from Glen Hazel 2 NE Dam, PA, which stands at 1,720 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 15857 (Saint Marys). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15845 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.