Last spring frost
May 18
Frost Dates for Lewis Run, PA
First fall frost
Oct 1
Growing season
136 days
Hardiness zone
5b
In an average year around Lewis Run, PA, the last spring frost (32°F) is about May 18 and the first fall frost is about Oct 1, giving roughly a 136-day growing season. To be safe most years, wait until Apr 30 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) | Jun 18 | Jun 1 | May 17 |
| Freeze (32°F) | May 31 | May 18 | Apr 30 |
| Hard (28°F) | May 21 | May 3 | Apr 18 |
| Severe (24°F) | May 8 | Apr 20 | Apr 3 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 18 | Jun 11 | Jun 8 | Jun 4 | Jun 1 | May 30 | May 27 | May 23 | May 17 |
| 32°F | May 31 | May 27 | May 24 | May 21 | May 18 | May 14 | May 10 | May 5 | Apr 30 |
| 28°F | May 21 | May 16 | May 10 | May 7 | May 3 | Apr 30 | Apr 27 | Apr 23 | Apr 18 |
| 24°F | May 8 | May 1 | Apr 28 | Apr 23 | Apr 20 | Apr 17 | Apr 13 | Apr 9 | Apr 3 |
| 20°F | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Apr 1 | Mar 28 | Mar 23 |
| 16°F | Apr 9 | Apr 4 | Apr 2 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 17 | Mar 13 |
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) | Aug 29 | Sep 19 | Oct 1 |
| Freeze (32°F) | Sep 18 | Oct 1 | Oct 15 |
| Hard (28°F) | Sep 30 | Oct 14 | Nov 2 |
| Severe (24°F) | Oct 11 | Oct 31 | Nov 17 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Aug 29 | Sep 5 | Sep 11 | Sep 15 | Sep 19 | Sep 22 | Sep 24 | Sep 28 | Oct 1 |
| 32°F | Sep 18 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 3 | Oct 6 | Oct 10 | Oct 15 |
| 28°F | Sep 30 | Oct 4 | Oct 6 | Oct 11 | Oct 14 | Oct 18 | Oct 21 | Oct 26 | Nov 2 |
| 24°F | Oct 11 | Oct 18 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 10 | Nov 17 |
| 20°F | Oct 26 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 16 | Nov 20 | Nov 25 | Dec 1 |
| 16°F | Nov 8 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 13 |
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: Bradford Rgnl Ap, Pa, about 3.3 miles away@if(!empty($station['elevation_ft'])), at 2,117 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 Lewis Run, PA?
On average, the last spring frost (32°F) around Lewis Run, PA is about May 18. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 30.
When is the first frost in the fall?
The first fall frost around Lewis Run, PA typically arrives about Oct 1. 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 18 on average, or Apr 30 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 136 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 16726 Planting calendar → Pennsylvania frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026