USDA Hardiness Zone 6b
Frost Dates for 15215 — Pittsburgh, Pennsylvania
NOAA 1991–2020 normals from Acmetonia Lock 3, PA (748 ft), 6 miles northeast.
Updated
In Pittsburgh, the last spring frost (32°F) is around April 16 in half of years and has passed by May 4 in nine years out of ten. The first fall frost comes around November 1, as early as October 18 one year in ten, leaving a typical freeze-free season of 197 days (NOAA, Acmetonia Lock 3, PA).
- Last spring frost
- April 16
- First fall frost
- November 1
- Growing season
- 197 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- December 9
- Last snow
- February 28
- Winters with snow
- 91%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
21 of 23 observed
NOAA normal
Frost risk by date in Pittsburgh
Half of springs at Acmetonia Lock 3, PA see their last 32°F night by April 16; only one in ten is past it by March 31, and one in ten still has one after May 4. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 27 20%, and after May 4 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 November 1 in half of years, as early as October 18 one year in ten, and holds off past November 13 one year in ten. A hard freeze of 28°F follows 10 days later, around November 11; in spring the one-in-ten date for 28°F is April 19, 15 days before the 32°F one. The freeze-free season lasts 197 days in a typical year, longer than at 86% of the 176 Pennsylvania stations; it reaches 216 days one year in ten and falls short of 175 one year in ten. On average 117 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 April 29, and return around October 20. Severe cold of 16°F or below comes every winter, usually between December 18 and March 6.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 13 | Apr 18 | Apr 22 | Apr 26 | Apr 29 | May 2 | May 5 | May 10 | May 17 |
| 32°F | Mar 31 | Apr 5 | Apr 8 | Apr 12 | Apr 16 | Apr 20 | Apr 23 | Apr 27 | May 4 |
| 28°F | Mar 19 | Mar 24 | Mar 29 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 14 | Apr 19 |
| 24°F | Mar 8 | Mar 14 | Mar 18 | Mar 21 | Mar 24 | Mar 27 | Mar 30 | Apr 2 | Apr 6 |
| 20°F | Feb 27 | Mar 4 | Mar 8 | Mar 11 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 29 |
| 16°F | Feb 13 | Feb 22 | Feb 28 | Mar 2 | Mar 6 | Mar 10 | Mar 13 | Mar 17 | Mar 22 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Nov 1 |
| 32°F | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 9 | Nov 13 |
| 28°F | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 25 |
| 24°F | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 2 | Dec 9 |
| 20°F | Nov 13 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 7 | Dec 12 | Dec 18 | Dec 24 |
| 16°F | Nov 24 | Dec 1 | Dec 7 | Dec 13 | Dec 18 | Dec 23 | Dec 27 | Jan 1 | Jan 8 |
Freeze probabilities 1991–2020 at Acmetonia Lock 3, 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 15215 →Compare Pittsburgh with another place →
Compared with the next station
The nearest other station, Braddock Lock 2, PA, 8 miles south of Pittsburgh, has a last frost 11 days earlier (April 5), a first frost 9 days later (November 10), a season 22 days longer.
When it snows in Pittsburgh, Pennsylvania
The first measurable snow (0.1 inch or more) in Pittsburgh usually arrives around December 9, and the last of the season around February 28. Those are the middle dates across the winters of 1991–2020 at Acmetonia Lock 3, PA, 5.9 miles away: half of years saw snow earlier, half later. Snow fell in 91% of those winters. The last 32°F night of spring typically comes 47 days after the last snow.
Planting calendar for 15215
| When | What to do |
|---|---|
| February 5 – February 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 19 – March 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 19 – April 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 9 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 18 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 1 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 15215 is 6 miles from Acmetonia Lock 3, PA, which stands at 748 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 15044 (Gibsonia). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15215 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.
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.