Pennsylvania frost dates
The typical last spring frost ranges from Mar 30 in Philadelphia to Apr 24 in Pittsburgh.
4 of the 4 Pennsylvania cities listed have typical frost dates. The longest frost-free season is 232 days in Philadelphia; the shortest is 184 days in Allentown. For a single address, look up your ZIP code: rural ZIPs use their nearest suitable station.
| City | Last spring frost | 1 in 10 after | First fall frost | 1 in 10 before | Hard freeze (28°F) | Season |
|---|---|---|---|---|---|---|
| Allentown | Apr 20 | May 6 | Oct 24 | Oct 8 | Apr 5 / Nov 4 | 184 days |
| Gettysburg | Apr 15 | May 4 | Oct 27 | Oct 11 | Apr 3 / Nov 8 | 194 days |
| Philadelphia | Mar 30 | Apr 12 | Nov 17 | Nov 4 | Mar 17 / Nov 29 | 232 days |
| Pittsburgh | Apr 24 | May 11 | Oct 27 | Oct 13 | Apr 12 / Nov 5 | 186 days |
Reading the table: Allentown
In Allentown, the last spring frost typically comes around Apr 20: in half of years it is earlier, in half later. In 1 year in 10 it comes after May 6, 16 days later, so tender plants set out after that date have a 90% chance of escaping frost. In fall, the first frost typically arrives around Oct 24, and in 1 year in 10 before Oct 8. Hard freezes (28°F) usually end earlier in spring and start later in fall: around Apr 5 and Nov 4 in Allentown.
Frost dates at more Pennsylvania weather stations
NOAA stations across Pennsylvania used by our ZIP code lookup, named for the town they are in.
| Station | Elevation | Last spring frost | First fall frost |
|---|---|---|---|
| Altoona Blair Co Airport | 1,480 ft | Apr 23 (1 in 10 after May 11) | Oct 21 (before Oct 5) |
| Bear Gap | 1,015 ft | Apr 27 (1 in 10 after May 15) | Oct 20 (before Oct 4) |
| Benton 3 Ne | 1,095 ft | May 4 (1 in 10 after May 19) | Oct 11 (before Sep 29) |
| Butler 2 Sw | 1,000 ft | May 7 (1 in 10 after May 23) | Oct 14 (before Oct 1) |
| Canton | 1,140 ft | May 16 (1 in 10 after May 29) | Oct 2 (before Sep 18) |
| Chambersburg 1 Ese | 640 ft | Apr 18 (1 in 10 after May 5) | Oct 25 (before Oct 10) |
| Clarion 3 Sw | 1,040 ft | May 9 (1 in 10 after May 24) | Oct 11 (before Sep 30) |
| Clearfield Lawrence Airport | 1,516 ft | May 4 (1 in 10 after May 22) | Oct 11 (before Sep 29) |
| Cowanesque Dam | 1,150 ft | May 9 (1 in 10 after May 25) | Oct 12 (before Sep 29) |
| Donegal 2 Nw | 1,800 ft | Apr 30 (1 in 10 after May 18) | Oct 17 (before Oct 3) |
| Donora 1 Sw | 762 ft | Apr 27 (1 in 10 after May 15) | Oct 22 (before Oct 8) |
| Doylestown Airport | 394 ft | Apr 13 (1 in 10 after Apr 27) | Oct 30 (before Oct 15) |
| Dubois Jefferson Co Airport | 1,814 ft | May 6 (1 in 10 after May 23) | Oct 14 (before Sep 29) |
| E Stroudsburg | 471 ft | May 1 (1 in 10 after May 18) | Oct 12 (before Oct 1) |
| Ebensburg Sewage Plt | 1,940 ft | May 17 (1 in 10 after Jun 1) | Oct 2 (before Sep 19) |
| Erie Intl Airport | 730 ft | Apr 26 (1 in 10 after May 13) | Nov 4 (before Oct 21) |
| Everett | 1,000 ft | Apr 27 (1 in 10 after May 16) | Oct 17 (before Oct 3) |
| Ford City 4 S Dam | 930 ft | May 4 (1 in 10 after May 20) | Oct 16 (before Oct 2) |
| Francis E Walter Dam | 1,509 ft | May 7 (1 in 10 after May 23) | Oct 6 (before Sep 22) |
| Franklin | 1,015 ft | May 2 (1 in 10 after May 20) | Oct 23 (before Oct 8) |
| Hamburg | 369 ft | Apr 16 (1 in 10 after May 3) | Oct 25 (before Oct 9) |
| Hawley 1 E | 890 ft | May 10 (1 in 10 after May 26) | Oct 4 (before Sep 21) |
| Indiana 3 Se | 1,102 ft | May 8 (1 in 10 after May 24) | Oct 13 (before Oct 1) |
| Johnstown Cambria Co Airport | 2,284 ft | Apr 29 (1 in 10 after May 17) | Oct 21 (before Oct 5) |
| Lancaster 2NE Fltr Plt | 270 ft | Apr 19 (1 in 10 after May 7) | Oct 24 (before Oct 9) |
| Landisville 2 Nw | 360 ft | Apr 30 (1 in 10 after May 13) | Oct 10 (before Sep 29) |
| Laporte | 1,966 ft | May 6 (1 in 10 after May 22) | Oct 7 (before Sep 24) |
| Lebanon 2 W | 450 ft | Apr 20 (1 in 10 after May 7) | Oct 25 (before Oct 10) |
| Lewistown | 460 ft | Apr 21 (1 in 10 after May 9) | Oct 24 (before Oct 7) |
| Mahanoy City 2 N | 1,710 ft | Apr 30 (1 in 10 after May 18) | Oct 22 (before Oct 7) |
| Mckeesport | 740 ft | May 2 (1 in 10 after May 20) | Oct 20 (before Oct 1) |
| Middletown Harrisburg Intl Airport | 312 ft | Apr 9 (1 in 10 after Apr 25) | Nov 2 (before Oct 18) |
| Montgomery L&D | 690 ft | Apr 28 (1 in 10 after May 15) | Oct 26 (before Oct 9) |
| Mt Pleasant | 1,003 ft | May 1 (1 in 10 after May 19) | Oct 13 (before Oct 3) |
| Mt Pocono Mountains Airport | 1,916 ft | May 6 (1 in 10 after May 23) | Oct 8 (before Sep 27) |
| New Castle 1 N | 825 ft | Apr 30 (1 in 10 after May 19) | Oct 23 (before Oct 6) |
| New Holland 2 Se | 605 ft | Apr 14 (1 in 10 after Apr 30) | Nov 1 (before Oct 17) |
| Philadelphia Intl Airport | 10 ft | Apr 2 (1 in 10 after Apr 13) | Nov 10 (before Oct 30) |
| Philipsburg 2 S | 1,720 ft | May 13 (1 in 10 after May 29) | Oct 1 (before Sep 19) |
| Phoenixville 1 E | 85 ft | Apr 18 (1 in 10 after May 4) | Oct 27 (before Oct 12) |
| Pittsburgh Allegheny Co Airport | 1,248 ft | Apr 18 (1 in 10 after May 6) | Oct 28 (before Oct 14) |
| Pittsburgh Intl Airport | 1,203 ft | Apr 23 (1 in 10 after May 12) | Oct 23 (before Oct 9) |
| Pleasant Mt 1 W | 1,800 ft | May 14 (1 in 10 after May 29) | Oct 1 (before Sep 21) |
| Port Meadville Airport | 1,400 ft | Apr 30 (1 in 10 after May 18) | Oct 23 (before Oct 6) |
| Pottstown Limerick Airport | 291 ft | Apr 20 (1 in 10 after May 6) | Oct 23 (before Oct 9) |
| Prince Gallitzin Sp | 1,520 ft | May 10 (1 in 10 after May 28) | Oct 5 (before Sep 24) |
| Putneyville 2 Se Dam | 1,280 ft | May 10 (1 in 10 after May 28) | Oct 12 (before Sep 30) |
| Raystown Lake 2 | 1,000 ft | Apr 19 (1 in 10 after May 7) | Oct 28 (before Oct 12) |
| Reading Spaatz Fld | 341 ft | Apr 14 (1 in 10 after Apr 30) | Oct 29 (before Oct 13) |
| Salina 3 W | 1,109 ft | Apr 29 (1 in 10 after May 17) | Oct 20 (before Oct 5) |
| Selinsgrove 2 S | 420 ft | Apr 25 (1 in 10 after May 10) | Oct 22 (before Oct 7) |
| Shippensburg | 680 ft | Apr 19 (1 in 10 after May 6) | Oct 24 (before Oct 9) |
| Slippery Rock 1 Ssw | 1,260 ft | May 7 (1 in 10 after May 25) | Oct 14 (before Oct 1) |
| State College | 1,170 ft | Apr 20 (1 in 10 after May 6) | Oct 26 (before Oct 10) |
| Uniontown 1 Ne | 956 ft | Apr 30 (1 in 10 after May 18) | Oct 18 (before Oct 5) |
| Waynesburg 1 E | 940 ft | May 3 (1 in 10 after May 21) | Oct 15 (before Oct 2) |
| Wellsboro 4 Sw | 1,818 ft | May 10 (1 in 10 after May 26) | Oct 5 (before Sep 23) |
| Wilkes-Barre Intl Airport | 930 ft | Apr 23 (1 in 10 after May 10) | Oct 20 (before Oct 4) |
| Williamsport | 520 ft | Apr 24 (1 in 10 after May 11) | Oct 23 (before Oct 6) |
| Willow Grove NAS | 361 ft | Apr 11 (1 in 10 after Apr 27) | Nov 1 (before Oct 17) |
32°F dates from NOAA 1991-2020 freeze probabilities for each city's station. "1 in 10 after": a 10% chance of a later spring frost (planting is 90% safe after it). How to read frost dates.