Pennsylvania frost dates: Last spring and first autumn frost at every NOAA station, 1991-2020
Across Pennsylvania's 160 NOAA stations with frost dates, the median last spring frost (32°F) runs from March 30 in Marcus Hook to May 24 in Kane; for half of its places it comes after April 30.
- Typical last spring frost
- April 30median of 108 places
- Typical first autumn frost
- October 19median of 108 places
- Earliest last frost
- March 30Marcus Hook
- Latest last frost
- May 24Kane
When is the last frost in Pennsylvania, town by town?
Each date is NOAA's: "after April 30 in half of years" means the last 32°F night of spring came after April 30 in half of the years 1991-2020. By the 1-in-10 date, the last frost has passed in nine years out of ten.
Find your town in the list, or look up a ZIP code for the stations nearest it.
| Place or station | Last frost (median) | 1 in 10 after | First frost (median) | 1 in 10 before | Growing season | Zone |
|---|---|---|---|---|---|---|
| Marcus Hook | March 30 | April 9 | November 16 | November 2 | 230 days | 8a |
| Phila Franklin Inst | March 30 | April 12 | November 17 | November 4 | 232 days | 7b |
| Safe Harbor Dam | April 1 | April 13 | November 10 | October 28 | 221 days | 7b |
| PhiladelphiaPhiladelphia International Airport | April 2 | April 13 | November 10 | October 30 | 224 days | 7b |
| Philadelphia NE Airport | April 4 | April 17 | November 7 | October 24 | 216 days | 7b |
| BraddockBraddock Lock 2 | April 5 | April 22 | November 10 | October 28 | 219 days | – |
| Glenwillard Dashields Lock and Dam | April 8 | April 26 | November 8 | October 27 | 212 days | – |
| Norristown | April 8 | April 23 | October 31 | October 14 | 203 days | – |
| HarrisburgHarrisburg Capitol Cy Airport | April 9 | April 25 | November 1 | October 16 | 205 days | 7b |
| MiddletownMiddletown Harrisburg Int'l Airport | April 9 | April 25 | November 2 | October 18 | 206 days | 7a |
| Reading (4 mi NNW) | April 10 | April 26 | October 31 | October 14 | 202 days | 7a |
| Glenmoore | April 11 | April 29 | November 1 | October 16 | 205 days | – |
| Willow GroveWillow Grove Naval Air Station | April 11 | April 27 | November 1 | October 17 | 205 days | – |
| CharleroiCharleroi Lock 4 | April 13 | May 5 | November 5 | October 25 | 205 days | – |
| DoylestownDoylestown Airport | April 13 | April 27 | October 30 | October 15 | 198 days | 7a |
| New Holland2 mi SE | April 14 | April 30 | November 1 | October 17 | 198 days | 7a |
| ReadingReading Regional Airport | April 14 | April 30 | October 29 | October 13 | 197 days | 7a |
| Biglerville | April 15 | May 4 | October 27 | October 11 | 194 days | 7a |
| Harrisburg (1 mi NE) | April 15 | May 2 | October 23 | October 7 | 189 days | 7b |
| Acmetonia Lock 3 | April 16 | May 4 | November 1 | October 18 | 197 days | – |
| Hamburg | April 16 | May 3 | October 25 | October 9 | 189 days | – |
| Hopewell Morgantown | April 16 | April 30 | October 27 | October 11 | 193 days | – |
| NatronaNatrona Lock 4 | April 16 | May 2 | November 2 | October 20 | 199 days | – |
| Bloserville (1 mi N) | April 18 | May 8 | October 26 | October 11 | 191 days | – |
| Chambersburg1 mi ESE | April 18 | May 5 | October 25 | October 10 | 188 days | 7a |
| LancasterLancaster Airport | April 18 | May 5 | October 25 | October 10 | 186 days | 7a |
| Phoenixville1 mi E | April 18 | May 4 | October 27 | October 12 | 192 days | 7a |
| West MifflinPittsburgh Allegheny County Airport | April 18 | May 6 | October 28 | October 14 | 193 days | 7a |
| Avondale2 mi N | April 19 | May 3 | October 26 | October 11 | 189 days | – |
| Coatesville2 mi W | April 19 | May 4 | October 25 | October 11 | 190 days | 7a |
| Lancaster 2 mi NE Filter Plant | April 19 | May 7 | October 24 | October 9 | 186 days | 7a |
| Raystown Headquarters | April 19 | May 8 | October 29 | October 13 | 194 days | – |
| Raystown Lake 2 | April 19 | May 7 | October 28 | October 12 | 191 days | 7a |
| Shippensburg | April 19 | May 6 | October 24 | October 9 | 188 days | 7a |
| AllentownAllentown Lehigh Valley International Airport | April 20 | May 6 | October 24 | October 8 | 184 days | 7a |
| Lebanon2 mi W | April 20 | May 7 | October 25 | October 10 | 185 days | 7a |
| PottstownPottstown Limerick Airport | April 20 | May 6 | October 23 | October 9 | 186 days | 7a |
| State College | April 20 | May 6 | October 26 | October 10 | 187 days | 7a |
| Lehighton1 mi SSW | April 21 | May 9 | October 23 | October 7 | 184 days | – |
| Lewistown | April 21 | May 9 | October 24 | October 7 | 185 days | 7a |
| Neshaminy Falls | April 21 | May 7 | October 25 | October 11 | 185 days | 7a |
| SchenleySchenley Lock 5 | April 21 | May 9 | October 30 | October 15 | 190 days | – |
| Springtown (1 mi NNE) | April 21 | May 6 | October 22 | October 7 | 184 days | 7a |
| Connellsville2 mi SSW | April 22 | May 11 | October 27 | October 14 | 187 days | – |
| Murrysville2 mi SW | April 22 | May 12 | October 25 | October 10 | 186 days | – |
| AltoonaAltoona Blair County Airport | April 23 | May 11 | October 21 | October 5 | 177 days | 6b |
| AvocaWilkes-Barre/Scranton International Airport | April 23 | May 10 | October 20 | October 4 | 178 days | 6b |
| CarlisleCarlisle Water Treatment Plant | April 23 | May 9 | October 18 | October 4 | 177 days | – |
| PittsburghPittsburgh International Airport | April 23 | May 12 | October 23 | October 9 | 181 days | 6b |
| Eisenhower National Historic Site | April 24 | May 10 | October 21 | October 6 | 180 days | – |
| EmsworthEmsworth L/D Ohio River | April 24 | May 11 | October 27 | October 13 | 186 days | – |
| Graterford (1 mi E) | April 24 | May 9 | October 15 | October 1 | 173 days | 6b |
| Hanover4 mi SW | April 24 | May 11 | October 20 | October 6 | 177 days | 6b |
| Washington3 mi NE | April 24 | May 18 | October 23 | October 8 | 181 days | 6b |
| WilliamsportWilliamsport Regional Airport | April 24 | May 11 | October 23 | October 6 | 180 days | 6b |
| Altoona (3 mi W) | April 25 | May 11 | October 21 | October 5 | 176 days | 6b |
| Altoona (7 mi SW) | April 25 | May 14 | October 20 | October 6 | 177 days | – |
| LaureltonLaurelton Center | April 25 | May 11 | October 19 | October 4 | 175 days | – |
| Selinsgrove (2 mi S) | April 25 | May 10 | October 22 | October 7 | 178 days | 6b |
| Williamsport 2 | April 25 | May 12 | October 24 | October 8 | 181 days | – |
| Blue Marsh Lake | April 26 | May 12 | October 19 | October 5 | 176 days | 7a |
| ErieErie International Airport | April 26 | May 13 | November 4 | October 21 | 192 days | 7a |
| Laurel Mountain | April 26 | May 13 | October 17 | October 4 | 172 days | – |
| Lewisburg | April 26 | May 11 | October 20 | October 5 | 176 days | 7a |
| Octoraro Lake | April 26 | May 10 | October 22 | October 9 | 179 days | 7a |
| Rodale Research Center | April 26 | May 13 | October 14 | October 1 | 171 days | – |
| Sellersville | April 26 | May 12 | October 17 | October 5 | 175 days | 7a |
| West Chester2 mi NW | April 26 | May 11 | October 18 | October 4 | 174 days | 7a |
| York 3 SSW Pump Station | April 26 | May 13 | October 19 | October 5 | 177 days | 7a |
| Bear Gap | April 27 | May 15 | October 20 | October 4 | 172 days | – |
| Beaver Falls1 mi NE | April 27 | May 16 | October 25 | October 7 | 178 days | – |
| Donora1 mi SW | April 27 | May 15 | October 22 | October 8 | 177 days | 6b |
| Everett | April 27 | May 16 | October 17 | October 3 | 170 days | 6b |
| SelinsgroveSelinsgrove Penn Valley Airport | April 27 | May 12 | October 16 | October 3 | 172 days | 6b |
| South Mountain | April 27 | May 14 | October 20 | October 6 | 177 days | 6b |
| YorkYork Airport | April 27 | May 11 | October 18 | October 4 | 174 days | 6b |
| Carnot-MoonMoon Twp | April 28 | May 15 | October 18 | October 5 | 172 days | – |
| Cashtown1 mi S | April 28 | May 16 | October 17 | October 4 | 170 days | – |
| Grays Landing | April 28 | May 14 | October 21 | October 9 | 175 days | 6b |
| Montgomery Lock and Dam | April 28 | May 15 | October 26 | October 9 | 178 days | 7a |
| Alvin R Bush Dam | April 29 | May 14 | October 21 | October 6 | 177 days | 6b |
| Bucksville | April 29 | May 15 | October 16 | October 4 | 170 days | 6b |
| JohnstownJohnstown Cambria County Airport | April 29 | May 17 | October 21 | October 5 | 176 days | 6b |
| Salina (3 mi W) | April 29 | May 17 | October 20 | October 5 | 171 days | 6a |
| Wolfsburg | April 29 | May 18 | October 13 | September 29 | 167 days | 6b |
| ConfluenceConfluence 1 SW Dam | April 30 | May 18 | October 18 | October 4 | 171 days | 6a |
| Donegal2 mi NW | April 30 | May 18 | October 17 | October 3 | 170 days | – |
| Landisville2 mi NW | April 30 | May 13 | October 10 | September 29 | 162 days | 6b |
| Linesville1 mi S | April 30 | May 17 | October 23 | October 6 | 177 days | 6a |
| Lock HavenLock Haven Sewage Plant | April 30 | May 15 | October 20 | October 5 | 173 days | 6b |
| Mahanoy City2 mi N | April 30 | May 18 | October 22 | October 7 | 175 days | – |
| New Castle1 mi N | April 30 | May 19 | October 23 | October 6 | 175 days | 6b |
| Point MarionPoint Marion Lock 8 | April 30 | May 17 | October 23 | October 9 | 177 days | – |
| Port Meadville Airport | April 30 | May 18 | October 23 | October 6 | 175 days | 6b |
| Renovo | April 30 | May 17 | October 22 | October 6 | 173 days | 6b |
| Sunbury | April 30 | May 19 | October 13 | September 30 | 166 days | 6b |
| Uniontown1 mi NE | April 30 | May 18 | October 18 | October 5 | 171 days | 6b |
| Dehart Dam | May 1 | May 20 | October 16 | October 3 | 168 days | 7a |
| East Stroudsburg | May 1 | May 18 | October 12 | October 1 | 163 days | 6b |
| Mount Pleasant | May 1 | May 19 | October 13 | October 3 | 164 days | – |
| TionestaTionesta 2 SE Lake | May 1 | May 18 | October 25 | October 8 | 176 days | 6a |
| Franklin | May 2 | May 20 | October 23 | October 8 | 171 days | 6b |
| Hidden Valley | May 2 | May 18 | October 17 | October 5 | 168 days | – |
| LoyalhannaLoyalhanna Lake | May 2 | May 18 | October 14 | October 2 | 163 days | – |
| Matamoras | May 2 | May 17 | October 12 | October 1 | 164 days | – |
| McKeesport | May 2 | May 20 | October 20 | October 1 | 170 days | 6b |
| Towanda1 mi S | May 2 | May 16 | October 15 | October 1 | 165 days | 6a |
| Milanville | May 3 | May 21 | October 9 | September 27 | 156 days | – |
| Waynesburg1 mi E | May 3 | May 21 | October 15 | October 2 | 164 days | 6b |
| Benton3 mi NE | May 4 | May 19 | October 11 | September 29 | 159 days | – |
| ClearfieldClearfield Lawrence Airport | May 4 | May 22 | October 11 | September 29 | 161 days | 6a |
| Ford CityFord City 4 S Dam | May 4 | May 20 | October 16 | October 2 | 164 days | 6a |
| Grampian1 mi E | May 4 | May 21 | October 13 | September 30 | 160 days | 6a |
| Jamestown2 mi NW | May 4 | May 22 | October 14 | October 1 | 161 days | 6a |
| Shawnee State Park | May 4 | May 21 | October 10 | September 28 | 158 days | 6b |
| Warren | May 4 | May 22 | October 21 | October 6 | 168 days | 6b |
| Millheim | May 5 | May 24 | October 6 | September 25 | 153 days | 6b |
| Rector (3 mi SSW) | May 5 | May 22 | October 6 | September 23 | 152 days | – |
| DuBoisDubois Jefferson County Airport | May 6 | May 23 | October 14 | September 29 | 160 days | 6a |
| Laporte | May 6 | May 22 | October 7 | September 24 | 154 days | 6a |
| Laurel Summit | May 6 | May 23 | October 12 | October 1 | 159 days | 6a |
| Mount PoconoPocono Mountains Municipal Airport | May 6 | May 23 | October 8 | September 27 | 154 days | 6a |
| TiogaTioga Hammond Dam | May 6 | May 23 | October 10 | September 30 | 158 days | – |
| Butler2 mi SW | May 7 | May 23 | October 14 | October 1 | 159 days | 6b |
| Emporium | May 7 | May 23 | October 15 | October 1 | 160 days | 6a |
| Francis E Walter Dam | May 7 | May 23 | October 6 | September 22 | 153 days | – |
| Slippery Rock1 mi SSW | May 7 | May 25 | October 14 | October 1 | 158 days | 6a |
| Union CityUnion City Filtration Plant | May 7 | May 24 | October 10 | September 29 | 155 days | – |
| Indiana3 mi SE | May 8 | May 24 | October 13 | October 1 | 157 days | 6a |
| Springboro3 mi WNW | May 8 | May 23 | October 16 | October 1 | 160 days | 6a |
| Clarion3 mi SW | May 9 | May 24 | October 11 | September 30 | 154 days | 6a |
| Cowanesque Dam | May 9 | May 25 | October 12 | September 29 | 155 days | 5b |
| Hawley1 mi E | May 10 | May 26 | October 4 | September 21 | 146 days | 6a |
| Prince Gallitzin State Park | May 10 | May 28 | October 5 | September 24 | 149 days | 6a |
| Putneyville 2 SE Dam | May 10 | May 28 | October 12 | September 30 | 155 days | 6a |
| Stevenson Dam | May 10 | May 27 | October 16 | October 2 | 157 days | 6a |
| Wellsboro4 mi SW | May 10 | May 26 | October 5 | September 23 | 148 days | 6a |
| Meyersdale2 mi SSW | May 12 | May 28 | October 5 | September 24 | 146 days | 6a |
| TitusvilleTitusville Water Works | May 12 | May 28 | October 10 | September 25 | 149 days | 5b |
| Cooksburg (2 mi NW) | May 13 | May 28 | October 7 | September 27 | 143 days | – |
| Philipsburg2 mi S | May 13 | May 29 | October 1 | September 19 | 142 days | 6a |
| Ridgway | May 13 | May 28 | October 11 | September 28 | 150 days | 5b |
| Coudersport (7 mi SE) | May 14 | May 30 | October 4 | September 21 | 143 days | – |
| Dushore | May 14 | May 27 | October 2 | September 20 | 143 days | 6a |
| Glen Hazel 2 NE Dam | May 14 | May 29 | October 6 | September 24 | 143 days | 5b |
| Montrose | May 14 | May 28 | October 2 | September 20 | 141 days | 5b |
| Pleasant Mount (1 mi W) | May 14 | May 29 | October 1 | September 21 | 140 days | 5b |
| Clermont (1 mi NW) | May 15 | May 31 | October 3 | September 21 | 140 days | 5b |
| Mercer | May 15 | June 1 | October 3 | September 19 | 140 days | – |
| Port Allegany | May 15 | May 29 | October 6 | September 25 | 144 days | 5b |
| Canton | May 16 | May 29 | October 2 | September 18 | 139 days | 5b |
| EbensburgEbensburg Sewage Plant | May 17 | June 1 | October 2 | September 19 | 136 days | 6a |
| BradfordBradford Regional Airport | May 18 | May 31 | October 1 | September 18 | 136 days | 5b |
| Bradford 4 mi SW Research 5 | May 18 | May 31 | October 4 | September 21 | 140 days | 5b |
| Chalk Hill (2 mi ENE) | May 19 | June 2 | October 1 | September 18 | 135 days | 6a |
| Oswayo1 mi ENE | May 20 | June 2 | September 29 | September 14 | 130 days | – |
| Clarence | May 21 | June 1 | September 27 | September 12 | 130 days | 5b |
| Chandlers Valley (1 mi SE) | May 22 | June 5 | September 30 | September 16 | 131 days | 5a |
| Coudersport1 mi SW | May 22 | June 6 | October 1 | September 19 | 130 days | 5b |
| Kane1 mi NNE | May 24 | June 7 | September 28 | September 11 | 126 days | 5a |
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities, growing-season length); station daily lows via ACIS (zone). Growing season: NOAA's median number of days between the last spring and first autumn 32°F night. Zone: the USDA's plant hardiness rule applied to the station's own 1991-2020 coldest nights.