USDA Hardiness Zone 6b
Frost Dates for 15022 — Charleroi, Pennsylvania
NOAA 1991–2020 normals from Charleroi Lock 4, PA (749 ft), 1 miles northeast.
Updated
In Charleroi, the last spring frost (32°F) is around April 13 in half of years and has passed by May 5 in nine years out of ten. The first fall frost comes around November 5, as early as October 25 one year in ten, leaving a typical freeze-free season of 205 days (NOAA, Charleroi Lock 4, PA).
- Last spring frost
- April 13
- First fall frost
- November 5
- Growing season
- 205 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 16
- Last snow
- March 1
- Winters with snow
- 92%
- Snow per year
- 10.3"
median, 1991–2020
median, 1991–2020
23 of 25 observed
NOAA normal
Frost risk by date in Charleroi
Half of springs at Charleroi Lock 4, PA see their last 32°F night by April 13; only one in ten is past it by March 29, and one in ten still has one after May 5. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 26 20%, and after May 5 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 99% of the 176 Pennsylvania stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by November 5 in half of years, as early as October 25 one year in ten, and holds off past November 18 one year in ten. A hard freeze of 28°F follows 11 days later, around November 16; in spring the one-in-ten date for 28°F is April 14, 21 days before the 32°F one. The freeze-free season lasts 205 days in a typical year, longer than at 92% of the 176 Pennsylvania stations; it reaches 227 days one year in ten and falls short of 182 one year in ten. On average 108 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 14 days longer, to about April 27, and return around October 25. Severe cold of 16°F or below comes every winter, usually between December 23 and February 28.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 11 | Apr 17 | Apr 20 | Apr 24 | Apr 27 | Apr 30 | May 4 | May 9 | May 16 |
| 32°F | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 13 | Apr 17 | Apr 21 | Apr 26 | May 5 |
| 28°F | Mar 15 | Mar 21 | Mar 25 | Mar 29 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 14 |
| 24°F | Mar 3 | Mar 9 | Mar 13 | Mar 17 | Mar 20 | Mar 23 | Mar 27 | Mar 31 | Apr 2 |
| 20°F | Feb 18 | Feb 26 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 16 | Mar 20 | Mar 25 |
| 16°F | Feb 5 | Feb 12 | Feb 18 | Feb 24 | Feb 28 | Mar 3 | Mar 8 | Mar 12 | Mar 17 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 10 | Oct 15 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 30 | Nov 2 | Nov 5 |
| 32°F | Oct 25 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 10 | Nov 14 | Nov 18 |
| 28°F | Nov 3 | Nov 7 | Nov 10 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 28 | Dec 3 |
| 24°F | Nov 9 | Nov 14 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 9 | Dec 16 |
| 20°F | Nov 19 | Nov 26 | Dec 1 | Dec 5 | Dec 9 | Dec 14 | Dec 19 | Dec 23 | Dec 29 |
| 16°F | Dec 1 | Dec 9 | Dec 14 | Dec 20 | Dec 23 | Dec 28 | Jan 1 | Jan 7 | Jan 15 |
Freeze probabilities 1991–2020 at Charleroi Lock 4, 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 15022 →Compare Charleroi with another place →
Compared with the next station
The nearest other station, Donora 1 SW, PA, 3 miles northeast of Charleroi, has a last frost 14 days later (April 27), a first frost 14 days earlier (October 22), a season 28 days shorter.
When it snows in Charleroi, Pennsylvania
The first measurable snow (0.1 inch or more) in Charleroi usually arrives around December 16, and the last of the season around March 1. Those are the middle dates across the winters of 1991–2020 at Charleroi Lock 4, PA, 1 miles away: half of years saw snow earlier, half later. Snow fell in 92% of those winters. The last 32°F night of spring typically comes 43 days after the last snow.
Planting calendar for 15022
| When | What to do |
|---|---|
| February 2 – February 16 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 16 – March 2 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 16 – March 30 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 13 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 13 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 5 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 15022 is 1 mile from Charleroi Lock 4, PA, which stands at 749 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 15063 (Monongahela). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15022 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.