Frost Dates for 16929 — Lawrenceville, Pennsylvania

Half of springs at Cowanesque Dam, PA see their last 32°F night by May 9; only one in ten is past it by April 25, and one in ten still has one after May 25. Planting tender crops after May 16 leaves a 30% risk of a frost on them, after May 20 20%, and after May 25 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 51% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 12 in half of years, as early as September 29 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 14 days later, around October 26; in spring the one-in-ten date for 28°F is May 14, 11 days before the 32°F one. The freeze-free season lasts 155 days in a typical year, shorter than at 82% of the 176 Pennsylvania stations; it reaches 177 days one year in ten and falls short of 134 one year in ten. On average 161 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 21, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 28 and March 27.

July is the warmest month at Cowanesque Dam, PA, averaging 81°F by day and 58°F at night; January is the coldest at 32°F and 15°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 73% of years.

Warmth for growing adds up to 2,365 growing degree days a year (base 50°F), fewer than at 84% of the 176 Pennsylvania stations. 31% of them (742) have built up by the end of June, and July adds the most, 604. Precipitation totals 37.1 inches a year, most in June (4.3") and least in February (1.7"); May to September bring 50% of it.

The nearest other station, Tioga Hammond Dam, PA, 5 miles south of Lawrenceville, has a last frost 3 days earlier (May 6), a first frost 2 days earlier (October 10), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Lawrenceville usually arrives around November 20, and the last of the season around April 7. Those are the middle dates across the winters of 1991–2020 at Cowanesque Dam, PA, 1.6 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 32 days after the last snow.

ZIP 16929 is 2 miles from Cowanesque Dam, PA, which stands at 1,150 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16929 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.