When to plant in Allentown, PA
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Allentown, Pennsylvania — all computed from Allentown's nearest NOAA weather station.
In zone 7a, Allentown supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
The average first fall frost in Allentown is now 8 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
ALLENTOWN INTL AP · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Allentown’s own odds, recorded at ALLENTOWN INTL AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 18 | May 2 | Apr 19 | Sep 29 | Oct 12 | Oct 28 |
| 32°F | May 6 | Apr 20 | Apr 6 | Oct 8 | Oct 24 | Nov 6 |
| 28°F | Apr 18 | Apr 5 | Mar 23 | Oct 19 | Nov 4 | Nov 18 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Allentown, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 21 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Allentown planting FAQ
When is the last spring frost in Allentown, PA?
Plan for the last spring frost in Allentown around April 20 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Allentown, PA?
The first fall frost in Allentown typically arrives around October 24 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Allentown in?
Allentown is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Allentown?
Allentown has about 187 frost-free days — a moderate growing season — between the average last spring frost (April 20) and first fall frost (October 24).
When should I plant tomatoes in Allentown?
For Allentown, sow tomatoes indoors about February 23–March 9 and move the seedlings out around April 27, after the last spring frost.
Never miss a window in Allentown
An email when it’s time to start seeds, transplant, and sow — timed to Allentown’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Fullerton · 4 km
- Emmaus · 7 km
- Bethlehem · 10 km
- Northampton · 11 km
- Easton · 24 km
- Phillipsburg · 28 km
- Pottstown · 41 km
- Lansdale · 43 km
Frost dates recorded at ALLENTOWN INTL AP, 7 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Allentown, PA — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00014737. Retrieved from https://blissgarden.com/pennsylvania/allentown.