USDA Hardiness Zone 6a
Frost Dates for 16127 — Grove City, Pennsylvania
NOAA 1991–2020 normals from Slippery Rock 1 SSW, PA (1,260 ft), 8 miles south.
Updated
In Grove City, the last spring frost (32°F) is around May 7 in half of years and has passed by May 25 in nine years out of ten. The first fall frost comes around October 14, as early as October 1 one year in ten, leaving a typical freeze-free season of 158 days (NOAA, Slippery Rock 1 SSW, PA).
- Last spring frost
- May 7
- First fall frost
- October 14
- Growing season
- 158 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- November 19
- Last snow
- April 3
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in Grove City
Half of springs at Slippery Rock 1 SSW, PA see their last 32°F night by May 7; only one in ten is past it by April 22, and one in ten still has one after May 25. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 19 20%, and after May 25 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 14 in half of years, as early as October 1 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 13 days later, around October 27; in spring the one-in-ten date for 28°F is May 15, 10 days before the 32°F one. The freeze-free season lasts 158 days in a typical year, shorter than at 77% of the 176 Pennsylvania stations; it reaches 180 days one year in ten and falls short of 136 one year in ten. On average 142 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 13 days longer, to about May 20, and return around October 1. Severe cold of 16°F or below comes every winter, usually between December 1 and March 20.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 1 | May 8 | May 13 | May 17 | May 20 | May 22 | May 26 | May 29 | Jun 2 |
| 32°F | Apr 22 | Apr 27 | Apr 30 | May 3 | May 7 | May 11 | May 15 | May 19 | May 25 |
| 28°F | Apr 11 | Apr 16 | Apr 20 | Apr 23 | Apr 26 | Apr 29 | May 3 | May 9 | May 15 |
| 24°F | Mar 31 | Apr 3 | Apr 7 | Apr 10 | Apr 13 | Apr 17 | Apr 20 | Apr 25 | May 4 |
| 20°F | Mar 15 | Mar 21 | Mar 27 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 10 | Apr 15 |
| 16°F | Mar 6 | Mar 11 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 28 | Mar 31 | Apr 4 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 22 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 15 |
| 32°F | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 16 | Oct 20 | Oct 24 | Oct 30 |
| 28°F | Oct 10 | Oct 17 | Oct 20 | Oct 24 | Oct 27 | Oct 31 | Nov 1 | Nov 5 | Nov 10 |
| 24°F | Oct 26 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 17 | Nov 22 |
| 20°F | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 21 | Nov 26 | Dec 1 | Dec 5 |
| 16°F | Nov 11 | Nov 18 | Nov 22 | Nov 26 | Dec 1 | Dec 3 | Dec 6 | Dec 11 | Dec 19 |
Freeze probabilities 1991–2020 at Slippery Rock 1 SSW, 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 16127 →Compare Grove City with another place →
Weather by month in Grove City
July is the warmest month at Slippery Rock 1 SSW, PA, averaging 81°F by day and 58°F at night; January is the coldest at 33°F and 17°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 66% of years.
Warmth for growing adds up to 2,473 growing degree days a year (base 50°F), fewer than at 80% of the 176 Pennsylvania stations. 33% of them (805) have built up by the end of June, and July adds the most, 609. Precipitation totals 45.3 inches a year, most in June (4.8") and least in February (2.7"); May to September bring 48% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 33 | 17 | 3.5 | 100% | 27 | 2 |
| Feb | 37 | 18 | 2.7 | 100% | 25 | 2 |
| Mar | 46 | 25 | 3.4 | 100% | 23 | 17 |
| Apr | 59 | 35 | 3.9 | 100% | 12 | 73 |
| May | 69 | 45 | 4.1 | 66% | 3 | 253 |
| Jun | 77 | 54 | 4.8 | 2% | 0 | 459 |
| Jul | 81 | 58 | 4.6 | 0% | 0 | 609 |
| Aug | 80 | 56 | 4.0 | 0% | 0 | 564 |
| Sep | 74 | 50 | 4.1 | 9% | <1 | 358 |
| Oct | 62 | 39 | 3.5 | 91% | 7 | 115 |
| Nov | 49 | 31 | 3.5 | 100% | 18 | 19 |
| Dec | 38 | 23 | 3.2 | 100% | 25 | 3 |
Monthly normals 1991–2020 at Slippery Rock 1 SSW, PA (1,260 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, Mercer, PA, 9 miles northwest of Grove City, has a last frost 8 days later (May 15), a first frost 11 days earlier (October 3), a season 18 days shorter.
When it snows in Grove City, Pennsylvania
The first measurable snow (0.1 inch or more) in Grove City usually arrives around November 19, and the last of the season around April 3. Those are the middle dates across the winters of 1991–2020 at Mercer, PA, 8.8 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 34 days after the last snow.
Planting calendar for 16127
| When | What to do |
|---|---|
| February 26 – March 12 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 12 – March 26 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 9 – April 23 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 7 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 22 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 30 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 14 onward | Plant 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 16127 is 8 miles from Slippery Rock 1 SSW, PA, which stands at 1,260 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16127 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.