Frost Dates for 17046 — Lebanon, Pennsylvania

Half of springs at Lebanon 2 W, PA see their last 32°F night by April 20; only one in ten is past it by April 5, and one in ten still has one after May 7. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after May 1 20%, and after May 7 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 25 in half of years, as early as October 10 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 11 days later, around November 5; in spring the one-in-ten date for 28°F is April 18, 19 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, longer than at 69% of the 176 Pennsylvania stations; it reaches 206 days one year in ten and falls short of 166 one year in ten. On average 120 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 2, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 19 and March 2.

July is the warmest month at Lebanon 2 W, PA, averaging 84°F by day and 64°F at night; January is the coldest at 37°F and 22°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 22% of years.

Warmth for growing adds up to 3,214 growing degree days a year (base 50°F), more than at 72% of the 176 Pennsylvania stations. 34% of them (1,091) have built up by the end of June, and July adds the most, 753. Precipitation totals 46.5 inches a year, most in July (4.9") and least in February (2.6"); May to September bring 49% of it.

The nearest other station, Landisville 2 NW, PA, 17 miles south of Lebanon, has a last frost 10 days later (April 30), a first frost 15 days earlier (October 10), a season 23 days shorter.

The first measurable snow (0.1 inch or more) in Lebanon usually arrives around December 10, and the last of the season around March 13. Those are the middle dates across the winters of 1991–2020 at Lebanon 2 W, PA, 2.8 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 38 days after the last snow.

ZIP 17046 is 3 miles from Lebanon 2 W, PA, which stands at 450 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 11 other ZIP codes share the station; its figures are presented in full for 17042 (Lebanon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 17046 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.