Frost Dates for 19464 — Pottstown, Pennsylvania

Half of springs at Pottstown Limerick Airport, 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 6. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after May 1 20%, and after May 6 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 23 in half of years, as early as October 9 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 21, 15 days before the 32°F one. The freeze-free season lasts 186 days in a typical year, longer than at 72% of the 176 Pennsylvania stations; it reaches 207 days one year in ten and falls short of 164 one year in ten. On average 111 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 12. Severe cold of 16°F or below comes every winter, usually between December 15 and March 3.

July is the warmest month at Pottstown Limerick Airport, 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 3,108 growing degree days a year (base 50°F), more than at 61% of the 176 Pennsylvania stations. 34% of them (1,047) have built up by the end of June, and July adds the most, 744. Precipitation totals 45.3 inches a year, most in September (4.8") and least in February (2.6"); May to September bring 47% of it.

The nearest other station, Graterford 1 E, PA, 11 miles east of Pottstown, has a last frost 4 days later (April 24), a first frost 8 days earlier (October 15), a season 13 days shorter.

Measurable snow is rare here: only 7 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Bechtelsville 1ENE, PA, 8.7 miles away, so there is no typical first-snow date to plan around.

ZIP 19464 is 4 miles from Pottstown Limerick Airport, PA, which stands at 291 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 19464 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.