Skip to content

USDA Hardiness Zone 6a

Frost Dates for 15610 — Acme, Pennsylvania

NOAA 1991–2020 normals from Donegal 2 NW, PA (1,800 ft), 1 miles southeast.

Updated

In Acme, the last spring frost (32°F) is around April 30 in half of years and has passed by May 18 in nine years out of ten. The first fall frost comes around October 17, as early as October 3 one year in ten, leaving a typical freeze-free season of 170 days (NOAA, Donegal 2 NW, PA).

Last spring frost
April 30

50% probability

First fall frost
October 17

50% probability

Growing season
170 days

freeze-free, 50%

Hardiness zone
6a

-10 to -5°F (-23.3 to -20.6°C) coldest night

First snow
November 19

median, 1991–2020

Last snow
March 31

median, 1991–2020

Winters with snow
100%

25 of 25 observed

Snow per year
—

NOAA normal

Frost risk by date in Acme

Half of springs at Donegal 2 NW, PA see their last 32°F night by April 30; only one in ten is past it by April 15, and one in ten still has one after May 18. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 18 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 17 in half of years, as early as October 3 one year in ten, and holds off past October 31 one year in ten. A hard freeze of 28°F follows 13 days later, around October 30; in spring the one-in-ten date for 28°F is May 8, 10 days before the 32°F one. The freeze-free season lasts 170 days in a typical year, shorter than at 60% of the 176 Pennsylvania stations; it reaches 191 days one year in ten and falls short of 146 one year in ten. On average 143 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 11 days longer, to about May 11, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 4 and March 17.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 25Apr 30May 4May 8May 11May 16May 20May 24May 29
32°FApr 15Apr 19Apr 23Apr 26Apr 30May 2May 7May 11May 18
28°FApr 3Apr 6Apr 11Apr 14Apr 17Apr 20Apr 25Apr 30May 8
24°FMar 22Mar 27Mar 31Apr 2Apr 5Apr 7Apr 11Apr 15Apr 20
20°FMar 11Mar 16Mar 20Mar 23Mar 26Mar 30Apr 1Apr 4Apr 9
16°FMar 1Mar 7Mar 11Mar 14Mar 17Mar 20Mar 23Mar 28Apr 1
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 23Sep 27Oct 1Oct 3Oct 6Oct 8Oct 11Oct 14Oct 19
32°FOct 3Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 31
28°FOct 13Oct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 8Nov 13
24°FOct 30Nov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 23Nov 29
20°FNov 6Nov 10Nov 14Nov 18Nov 23Nov 26Nov 30Dec 4Dec 10
16°FNov 14Nov 21Nov 26Nov 30Dec 4Dec 7Dec 12Dec 19Dec 26

Freeze probabilities 1991–2020 at Donegal 2 NW, PA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 15610 →Compare Acme with another place →

Weather by month in Acme

July is the warmest month at Donegal 2 NW, PA, averaging 81°F by day and 60°F at night; January is the coldest at 35°F and 19°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 46% of years.

Warmth for growing adds up to 2,688 growing degree days a year (base 50°F), fewer than at 68% of the 176 Pennsylvania stations. 34% of them (920) have built up by the end of June, and July adds the most, 625.

Monthly normals 1991–2020 at Donegal 2 NW, PA
MonthHigh °FLow °F32°F nightNights ≤ 32°FGDD 50°F
Jan3519100%283
Feb3920100%245
Mar4726100%2420
Apr6037100%13103
May704746%3289
Jun77560%<1500
Jul81600%0625
Aug79590%0592
Sep74526%<1385
Oct634191%8134
Nov5132100%1826
Dec4125100%266

Monthly normals 1991–2020 at Donegal 2 NW, PA (1,800 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Mt Pleasant, PA, 7 miles northwest of Acme and 797 feet lower, has a last frost 1 day later (May 1), a first frost 4 days earlier (October 13), a season 6 days shorter.

Frost dates for 15601 (Greensburg) →

When it snows in Acme, Pennsylvania

The first measurable snow (0.1 inch or more) in Acme usually arrives around November 19, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Donegal 2 NW, PA, 1.2 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 30 days after the last snow.

Planting calendar for 15610

What to do and when, from the 50% frost dates for Acme, Pennsylvania
WhenWhat to do
February 19 – March 5Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 5 – March 19Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 2 – April 16Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 30 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 25Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by October 3Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 17 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 15610 is 1 mile from Donegal 2 NW, PA, which stands at 1,800 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 15610 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.

Frost dates across Pennsylvania →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

ZIP codes measured at the same station

Other zone 6a places in Pennsylvania