Frost Dates for 17754 — Montoursville, Pennsylvania

Half of springs at Williamsport, PA see their last 32°F night by April 24; only one in ten is past it by April 12, and one in ten still has one after May 11. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 6 20%, and after May 11 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 50% 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 5 one year in ten. A hard freeze of 28°F follows 11 days later, around November 3; in spring the one-in-ten date for 28°F is April 29, 12 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, longer than at 64% of the 176 Pennsylvania stations; it reaches 199 days one year in ten and falls short of 158 one year in ten. On average 122 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 12 days longer, to about May 6, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 10 and March 10.

July is the warmest month at Williamsport, PA, averaging 85°F by day and 63°F at night; January is the coldest at 35°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 31% of years.

Warmth for growing adds up to 3,083 growing degree days a year (base 50°F), more than at 57% of the 176 Pennsylvania stations. 34% of them (1,051) have built up by the end of June, and July adds the most, 736. Precipitation totals 43.7 inches a year, most in September (4.8") and least in February (2.3"); May to September bring 49% of it.

The nearest other station, Williamsport 2, PA, 4 miles west of Montoursville, has a last frost 1 day later (April 25), a first frost 1 day later (October 24), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Montoursville usually arrives around November 22, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Williamsport, PA, 2.1 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 29 days after the last snow.

ZIP 17754 is 2 miles from Williamsport, PA, which stands at 520 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 17756 (Muncy). The 2023 USDA Plant Hardiness Zone Map lists ZIP 17754 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.