In Pennsylvania, the last spring frost usually comes between April 17 and May 19, and the first fall frost between October 1 and October 30, depending on where you live. Most of Pennsylvania is in USDA hardiness zones 6a to 7b.
Find the frost dates for your ZIP code
Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Frost dates for Pennsylvania cities
Dates come from the NOAA weather station closest to each city. The last spring frost and first fall frost are the typical dates, with a 30% chance of frost after (or before) them. The safer planting date has only a 10% chance of a later spring frost: use it for tender plants like tomatoes, peppers and basil.
| City | Zone | Last frost | Safer date | First frost |
|---|---|---|---|---|
| Philadelphia | 7b | April 4 | April 12 | Nov. 11 |
| Pittsburgh | 6b | April 24 | May 6 | Oct. 22 |
| Allentown | 7a | April 26 | May 6 | Oct. 17 |
| Erie | 7a | May 2 | May 13 | Oct. 30 |
| Reading | 7a | April 21 | April 30 | Oct. 22 |
| Scranton | 6b | April 30 | May 10 | Oct. 13 |
| Lancaster | 7a | April 27 | May 7 | Oct. 17 |
| Harrisburg | 7a | April 21 | May 2 | Oct. 16 |
| Altoona | 6b | May 1 | May 11 | Oct. 15 |
| State College | 6b | April 27 | May 6 | Oct. 20 |
Frost dates vary a lot across Pennsylvania. Among the cities above, Philadelphia has the earliest last frost (around April 4) and Erie the latest (around May 2), about 4 weeks apart. Elevation, nearby water and local terrain all make a difference, so use the dates for the place closest to you, or look up your ZIP code.
Growing zones in Pennsylvania
Most of Pennsylvania is in USDA hardiness zones 6a to 7b. A typical frost-free growing season lasts about 184 days, longer in the warmest areas and shorter in the coldest.
Find planting dates for the main zones in Pennsylvania:
- Zone 6 (about 65% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
- Zone 7 (about 31% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
See all crops in our planting guides, or build a planting calendar for your ZIP code.
How to use frost dates
- Cool-season crops such as peas, lettuce, spinach and onions can go in several weeks before your last spring frost.
- Warm-season crops such as tomatoes, peppers, squash and beans wait until after it, when the soil has warmed.
- Fall crops are timed back from your first fall frost, and garlic and tulips are planted around it.
- Frost dates are averages. Check the forecast before setting out tender plants.
Frequently asked questions
When is the last frost in Pennsylvania?
It depends on where you live. Across most of Pennsylvania, the last spring frost comes between April 17 and May 19. In Philadelphia, it is around April 4.
When is the first frost in Pennsylvania?
Across most of Pennsylvania, the first fall frost comes between October 1 and October 30. In Philadelphia, it is around November 11.
What planting zone is Pennsylvania?
Most of Pennsylvania is in USDA hardiness zones 6a to 7b. Enter your ZIP code above to find your exact zone.
When can I plant tomatoes in Pennsylvania?
Plant tomatoes outside after your last frost, once nights stay above 50 °F. In Philadelphia, the safer date, with only a 10% chance of a later frost, is around April 12. See when to plant tomatoes in zone 7.
Sources. Frost dates come from the nearest NOAA weather station to each city or ZIP code. Zones come from the 2023 USDA Plant Hardiness Zone Map ZIP code data. Our zone lookup is not the official USDA map.