USDA Hardiness Zone 6a
Frost Dates for 15557 — Rockwood, Pennsylvania
NOAA 1991–2020 normals from Hidden Valley, PA (2,876 ft), 8 miles north.
Updated
In Rockwood, the last spring frost (32°F) is around May 2 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 5 one year in ten, leaving a typical freeze-free season of 168 days (NOAA, Hidden Valley, PA).
- Last spring frost
- May 2
- First fall frost
- October 17
- Growing season
- 168 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 8
- Last snow
- April 8
- Winters with snow
- 100%
- Snow per year
- 96.2"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Rockwood
Half of springs at Hidden Valley, PA see their last 32°F night by May 2; only one in ten is past it by April 19, and one in ten still has one after May 18. Planting tender crops after May 8 leaves a 30% risk of a frost on them, after May 12 20%, and after May 18 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 17 in half of years, as early as October 5 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 11 days later, around October 28; 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 168 days in a typical year, shorter than at 63% of the 176 Pennsylvania stations; it reaches 187 days one year in ten and falls short of 149 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 9 days longer, to about May 11, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 30 and March 20.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 28 | May 2 | May 5 | May 8 | May 11 | May 15 | May 18 | May 22 | May 26 |
| 32°F | Apr 19 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 5 | May 8 | May 12 | May 18 |
| 28°F | Apr 9 | Apr 13 | Apr 17 | Apr 19 | Apr 22 | Apr 24 | Apr 28 | May 2 | May 8 |
| 24°F | Mar 28 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 13 | Apr 16 | Apr 19 | Apr 26 |
| 20°F | Mar 16 | Mar 22 | Mar 26 | Mar 29 | Apr 1 | Apr 3 | Apr 5 | Apr 9 | Apr 14 |
| 16°F | Mar 5 | Mar 11 | Mar 15 | Mar 17 | Mar 20 | Mar 23 | Mar 27 | Mar 31 | Apr 3 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 11 | Oct 14 | Oct 19 |
| 32°F | Oct 5 | Oct 8 | Oct 12 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 25 | Oct 30 |
| 28°F | Oct 14 | Oct 19 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 11 |
| 24°F | Oct 27 | Nov 1 | Nov 3 | Nov 6 | Nov 8 | Nov 11 | Nov 14 | Nov 17 | Nov 22 |
| 20°F | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 4 |
| 16°F | Nov 12 | Nov 17 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 12 | Dec 20 |
Freeze probabilities 1991–2020 at Hidden Valley, 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 15557 →Compare Rockwood with another place →
Compared with the next station
The nearest other station, Confluence 1 SW Dam, PA, 12 miles southwest of Rockwood and 1,386 feet lower, has a last frost 2 days earlier (April 30), a first frost 1 day later (October 18), a season 3 days longer.
When it snows in Rockwood, Pennsylvania
The first measurable snow (0.1 inch or more) in Rockwood usually arrives around November 8, and the last of the season around April 8. Those are the middle dates across the winters of 1991–2020 at Somerset, PA, 8.4 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 24 days after the last snow.
Planting calendar for 15557
| When | What to do |
|---|---|
| February 21 – March 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 7 – March 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 4 – April 18 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 25 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 3 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 17 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 15557 is 8 miles from Hidden Valley, PA, which stands at 2,876 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 15501 (Somerset). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15557 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.