Last spring frost
May 2
Frost Dates for Coulter, PA
First fall frost
Oct 20
Growing season
170 days
Hardiness zone
6b
In an average year around Coulter, PA, the last spring frost (32°F) is about May 2 and the first fall frost is about Oct 20, giving roughly a 170-day growing season. To be safe most years, wait until Apr 17 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 27 | May 12 | Apr 26 |
| Freeze (32°F) | May 20 | May 2 | Apr 17 |
| Hard (28°F) | May 10 | Apr 20 | Apr 2 |
| Severe (24°F) | Apr 30 | Apr 4 | Mar 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 27 | May 23 | May 19 | May 15 | May 12 | May 8 | May 4 | Apr 30 | Apr 26 |
| 32°F | May 20 | May 14 | May 10 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 17 |
| 28°F | May 10 | May 4 | Apr 29 | Apr 24 | Apr 20 | Apr 16 | Apr 13 | Apr 7 | Apr 2 |
| 24°F | Apr 30 | Apr 19 | Apr 13 | Apr 7 | Apr 4 | Apr 1 | Mar 29 | Mar 24 | Mar 18 |
| 20°F | Apr 10 | Apr 3 | Mar 31 | Mar 27 | Mar 22 | Mar 18 | Mar 15 | Mar 11 | Mar 4 |
| 16°F | Mar 30 | Mar 22 | Mar 18 | Mar 15 | Mar 10 | Mar 7 | Mar 3 | Feb 28 | Feb 19 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 21 | Oct 7 | Oct 24 |
| Freeze (32°F) | Oct 1 | Oct 20 | Nov 3 |
| Hard (28°F) | Oct 10 | Nov 1 | Nov 14 |
| Severe (24°F) | Oct 28 | Nov 12 | Dec 1 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 28 | Oct 2 | Oct 5 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 24 |
| 32°F | Oct 1 | Oct 6 | Oct 11 | Oct 15 | Oct 20 | Oct 24 | Oct 27 | Oct 31 | Nov 3 |
| 28°F | Oct 10 | Oct 20 | Oct 25 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 14 |
| 24°F | Oct 28 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 23 | Dec 1 |
| 20°F | Nov 8 | Nov 13 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 16 |
| 16°F | Nov 18 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 15 | Dec 20 | Dec 25 | Jan 1 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Mckeesport, Pa, about 4.4 miles away@if(!empty($station['elevation_ft'])), at 740 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Coulter, PA?
On average, the last spring frost (32°F) around Coulter, PA is about May 2. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 17.
When is the first frost in the fall?
The first fall frost around Coulter, PA typically arrives about Oct 20. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around May 2 on average, or Apr 17 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 170 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 15028 Planting calendar → Pennsylvania frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026