Last spring frost
Apr 13
Frost Dates for Chalfont, PA
First fall frost
Oct 30
Growing season
198 days
Hardiness zone
7a
In an average year around Chalfont, PA, the last spring frost (32°F) is about Apr 13 and the first fall frost is about Oct 30, giving roughly a 198-day growing season. To be safe most years, wait until Apr 1 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 11 | Apr 27 | Apr 14 |
| Freeze (32°F) | Apr 27 | Apr 13 | Apr 1 |
| Hard (28°F) | Apr 14 | Apr 2 | Mar 17 |
| Severe (24°F) | Apr 3 | Mar 21 | Mar 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 11 | May 6 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 14 |
| 32°F | Apr 27 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 11 | Apr 7 | Apr 4 | Apr 1 |
| 28°F | Apr 14 | Apr 9 | Apr 6 | Apr 3 | Apr 2 | Mar 31 | Mar 28 | Mar 23 | Mar 17 |
| 24°F | Apr 3 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 18 | Mar 15 | Mar 11 | Mar 6 |
| 20°F | Mar 27 | Mar 21 | Mar 18 | Mar 15 | Mar 12 | Mar 8 | Mar 5 | Feb 28 | Feb 22 |
| 16°F | Mar 19 | Mar 13 | Mar 8 | Mar 4 | Feb 28 | Feb 24 | Feb 19 | Feb 13 | Feb 5 |
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) | Oct 5 | Oct 18 | Nov 1 |
| Freeze (32°F) | Oct 15 | Oct 30 | Nov 12 |
| Hard (28°F) | Oct 27 | Nov 10 | Nov 25 |
| Severe (24°F) | Nov 8 | Nov 24 | Dec 10 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 |
| 32°F | Oct 15 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 8 | Nov 12 |
| 28°F | Oct 27 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 12 | Nov 16 | Nov 19 | Nov 25 |
| 24°F | Nov 8 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 27 | Nov 30 | Dec 3 | Dec 10 |
| 20°F | Nov 17 | Nov 23 | Nov 29 | Dec 2 | Dec 5 | Dec 8 | Dec 14 | Dec 20 | Dec 26 |
| 16°F | Dec 1 | Dec 7 | Dec 12 | Dec 18 | Dec 22 | Dec 25 | Dec 30 | Jan 4 | Jan 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: Doylestown Ap, Pa, about 5.4 miles away@if(!empty($station['elevation_ft'])), at 394 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 Chalfont, PA?
On average, the last spring frost (32°F) around Chalfont, PA is about Apr 13. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 1.
When is the first frost in the fall?
The first fall frost around Chalfont, PA typically arrives about Oct 30. 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 Apr 13 on average, or Apr 1 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 198 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 18914 Planting calendar → Pennsylvania frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026