Frost Dates for 15650 — Latrobe, Pennsylvania

Half of springs at Mt Pleasant, PA see their last 32°F night by May 1; only one in ten is past it by April 17, and one in ten still has one after May 19. Planting tender crops after May 8 leaves a 30% risk of a frost on them, after May 13 20%, and after May 19 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 70% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 13 in half of years, as early as October 3 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 11 days later, around October 24; in spring the one-in-ten date for 28°F is May 8, 11 days before the 32°F one. The freeze-free season lasts 164 days in a typical year, shorter than at 68% of the 176 Pennsylvania stations; it reaches 184 days one year in ten and falls short of 145 one year in ten. On average 130 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 13, and return around October 3. Severe cold of 16°F or below comes every winter, usually between November 30 and March 16.

July is the warmest month at Mt Pleasant, PA, averaging 82°F by day and 60°F at night; January is the coldest at 37°F and 21°F. A freezing night is all but certain in every month from October 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 52% of years.

Warmth for growing adds up to 2,814 growing degree days a year (base 50°F), fewer than at 61% of the 176 Pennsylvania stations. 34% of them (967) have built up by the end of June, and July adds the most, 654. Precipitation totals 44.0 inches a year, most in June (4.9") and least in February (2.2"); May to September bring 48% of it.

The nearest other station, Loyalhanna Lake, PA, 11 miles north of Latrobe, has a last frost 1 day later (May 2), a first frost 1 day later (October 14), a season 1 day shorter.

The first measurable snow (0.1 inch or more) in Latrobe usually arrives around November 29, and the last of the season around March 27. Those are the middle dates across the winters of 1991–2020 at Derry 4 SW, PA, 2.9 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 35 days after the last snow.

ZIP 15650 is 8 miles from Mt Pleasant, PA, which stands at 1,003 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 15601 (Greensburg). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15650 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.