Frost dates in Pennsylvania
Across Pennsylvania, the typical last spring frost is around Apr 27 and the first fall frost around Oct 21. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Apr 11 and May 10, and its first fall frosts between Oct 5 and Nov 2.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Pennsylvania: zone 5a, zone 5b, zone 6a, zone 6b, zone 7a, zone 7b, zone 8a
Frost dates by county in Pennsylvania
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Adams | Apr 24 | Oct 20 | About 179 days |
| Allegheny | Apr 18 | Oct 28 | About 193 days |
| Armstrong | May 4 | Oct 16 | About 165 days |
| Beaver | Apr 27 | Oct 26 | About 182 days |
| Bedford | Apr 27 | Oct 17 | About 173 days |
| Berks | Apr 16 | Oct 25 | About 192 days |
| Blair | Apr 25 | Oct 21 | About 179 days |
| Bradford | May 6 | Oct 10 | About 157 days |
| Bucks | Apr 21 | Oct 25 | About 187 days |
| Butler | May 7 | Oct 14 | About 160 days |
| Cambria | May 10 | Oct 5 | About 148 days |
| Cameron | May 10 | Oct 16 | About 159 days |
| Carbon | Apr 21 | Oct 23 | About 185 days |
| Centre | Apr 30 | Oct 19 | About 172 days |
| Chester | Apr 19 | Oct 26 | About 190 days |
| Clarion | May 9 | Oct 11 | About 155 days |
| Clearfield | May 10 | Oct 5 | About 148 days |
| Clinton | Apr 30 | Oct 20 | About 173 days |
| Columbia | Apr 27 | Oct 20 | About 176 days |
| Crawford | May 4 | Oct 16 | About 165 days |
| Cumberland | Apr 18 | Oct 24 | About 189 days |
| Dauphin | Apr 25 | Oct 23 | About 181 days |
| Delaware | Apr 2 | Nov 10 | About 222 days |
| Elk | May 13 | Oct 11 | About 151 days |
| Erie | Apr 26 | Nov 4 | About 192 days |
| Fayette | Apr 30 | Oct 18 | About 171 days |
| Forest | May 1 | Oct 25 | About 177 days |
| Franklin | Apr 19 | Oct 24 | About 188 days |
| Fulton | Apr 27 | Oct 17 | About 173 days |
| Greene | May 3 | Oct 15 | About 165 days |
| Huntingdon | Apr 19 | Oct 28 | About 192 days |
| Indiana | May 8 | Oct 13 | About 158 days |
| Jefferson | May 9 | Oct 14 | About 158 days |
| Juniata | Apr 21 | Oct 24 | About 186 days |
| Lackawanna | Apr 23 | Oct 20 | About 180 days |
| Lancaster | Apr 18 | Oct 25 | About 190 days |
| Lawrence | Apr 30 | Oct 23 | About 176 days |
| Lebanon | Apr 20 | Oct 25 | About 188 days |
| Lehigh | Apr 21 | Oct 23 | About 185 days |
| Luzerne | Apr 30 | Oct 20 | About 173 days |
| Lycoming | Apr 25 | Oct 23 | About 181 days |
| McKean | May 15 | Oct 3 | About 141 days |
| Mercer | May 15 | Oct 14 | About 152 days |
| Mifflin | Apr 21 | Oct 24 | About 186 days |
| Monroe | May 6 | Oct 8 | About 155 days |
| Montgomery | Apr 11 | Oct 31 | About 203 days |
| Montour | Apr 27 | Oct 20 | About 176 days |
| Northampton | Apr 20 | Oct 24 | About 187 days |
| Northumberland | Apr 27 | Oct 20 | About 176 days |
| Perry | Apr 18 | Oct 24 | About 189 days |
| Philadelphia | Mar 30 | Nov 17 | About 232 days |
| Pike | May 10 | Oct 11 | About 154 days |
| Potter | May 15 | Oct 4 | About 142 days |
| Schuylkill | Apr 30 | Oct 22 | About 175 days |
| Snyder | Apr 25 | Oct 19 | About 177 days |
| Somerset | May 6 | Oct 12 | About 159 days |
| Sullivan | May 6 | Oct 7 | About 154 days |
| Susquehanna | May 14 | Oct 2 | About 141 days |
| Tioga | May 10 | Oct 5 | About 148 days |
| Union | Apr 25 | Oct 19 | About 177 days |
| Venango | May 2 | Oct 23 | About 174 days |
| Warren | May 22 | Sep 30 | About 131 days |
| Washington | Apr 23 | Oct 23 | About 183 days |
| Wayne | May 10 | Oct 4 | About 147 days |
| Westmoreland | Apr 30 | Oct 17 | About 170 days |
| Wyoming | Apr 23 | Oct 20 | About 180 days |
| York | Apr 19 | Oct 25 | About 189 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.