Last frost dates in Pennsylvania
160 NOAA weather stations in Pennsylvania have thirty years of frost records. The median station sees its last 32 °F night around Apr 28; across the state that ranges from Mar 30 to May 24, so pick the station nearest you rather than a state-wide figure.
| MARCUS HOOK | Mar 30 | Apr 9 | Mar 16 | Nov 16 | 230 |
| PHILA FRANKLIN INST | Mar 30 | Apr 12 | Mar 15 | Nov 17 | 232 |
| SAFE HARBOR DAM | Apr 1 | Apr 13 | Mar 18 | Nov 10 | 221 |
| PHILADELPHIA INTL AP | Apr 2 | Apr 13 | Mar 19 | Nov 10 | 224 |
| PHILADELPHIA NE AP | Apr 4 | Apr 17 | Mar 21 | Nov 7 | 216 |
| BRADDOCK LOCK 2 | Apr 5 | Apr 22 | Mar 22 | Nov 10 | 219 |
| GLENWILLARD DASHIELDS L&D | Apr 8 | Apr 26 | Mar 25 | Nov 8 | 212 |
| NORRISTOWN | Apr 8 | Apr 23 | Mar 28 | Oct 31 | 203 |
| HARRISBURG CPTL CY AP | Apr 9 | Apr 25 | Mar 27 | Nov 1 | 205 |
| MIDDLETOWN HARRISBURG INTL AP | Apr 9 | Apr 25 | Mar 28 | Nov 2 | 206 |
| READING 4 NNW | Apr 10 | Apr 26 | Mar 29 | Oct 31 | 202 |
| GLENMOORE | Apr 11 | Apr 29 | Mar 28 | Nov 1 | 205 |
| WILLOW GROVE NAS | Apr 11 | Apr 27 | Mar 29 | Nov 1 | 205 |
| CHARLEROI LOCK 4 | Apr 13 | May 5 | Mar 29 | Nov 5 | 205 |
| DOYLESTOWN AP | Apr 13 | Apr 27 | Apr 1 | Oct 30 | 198 |
| NEW HOLLAND 2 SE | Apr 14 | Apr 30 | Apr 1 | Nov 1 | 198 |
| READING SPAATZ FLD | Apr 14 | Apr 30 | Apr 1 | Oct 29 | 197 |
| BIGLERVILLE | Apr 15 | May 4 | Apr 1 | Oct 27 | 194 |
| HARRISBURG 1 NE | Apr 15 | May 2 | Apr 1 | Oct 23 | 189 |
| ACMETONIA LOCK 3 | Apr 16 | May 4 | Mar 31 | Nov 1 | 197 |
| HAMBURG | Apr 16 | May 3 | Apr 2 | Oct 25 | 189 |
| HOPEWELL MORGANTOWN | Apr 16 | Apr 30 | Apr 3 | Oct 27 | 193 |
| NATRONA LOCK 4 | Apr 16 | May 2 | Mar 31 | Nov 2 | 199 |
| BLOSERVILLE 1 N | Apr 18 | May 8 | Apr 3 | Oct 26 | 191 |
| CHAMBERSBURG 1 ESE | Apr 18 | May 5 | Apr 3 | Oct 25 | 188 |
| LANCASTER AP | Apr 18 | May 5 | Apr 4 | Oct 25 | 186 |
| PHOENIXVILLE 1 E | Apr 18 | May 4 | Apr 3 | Oct 27 | 192 |
| PITTSBURGH ALLEGHENY CO AP | Apr 18 | May 6 | Apr 2 | Oct 28 | 193 |
| AVONDALE 2 N | Apr 19 | May 3 | Apr 1 | Oct 26 | 189 |
| COATESVILLE 2 W | Apr 19 | May 4 | Apr 3 | Oct 25 | 190 |
| LANCASTER 2NE FLTR PLT | Apr 19 | May 7 | Apr 5 | Oct 24 | 186 |
| RAYSTOWN HQ | Apr 19 | May 8 | Apr 4 | Oct 29 | 194 |
| RAYSTOWN LAKE 2 | Apr 19 | May 7 | Apr 5 | Oct 28 | 191 |
| SHIPPENSBURG | Apr 19 | May 6 | Apr 4 | Oct 24 | 188 |
| ALLENTOWN INTL AP | Apr 20 | May 6 | Apr 6 | Oct 24 | 184 |
| LEBANON 2 W | Apr 20 | May 7 | Apr 5 | Oct 25 | 185 |
| POTTSTOWN LIMERICK AP | Apr 20 | May 6 | Apr 5 | Oct 23 | 186 |
| STATE COLLEGE | Apr 20 | May 6 | Apr 7 | Oct 26 | 187 |
| LEHIGHTON 1SSW | Apr 21 | May 9 | Apr 7 | Oct 23 | 184 |
| LEWISTOWN | Apr 21 | May 9 | Apr 6 | Oct 24 | 185 |
| NESHAMINY FALLS | Apr 21 | May 7 | Apr 6 | Oct 25 | 185 |
| SCHENLEY LOCK 5 | Apr 21 | May 9 | Apr 6 | Oct 30 | 190 |
| SPRINGTOWN 1 NNE | Apr 21 | May 6 | Apr 8 | Oct 22 | 184 |
| CONNELLSVILLE 2 SSW | Apr 22 | May 11 | Apr 6 | Oct 27 | 187 |
| MURRYSVILLE 2 SW | Apr 22 | May 12 | Apr 7 | Oct 25 | 186 |
| ALTOONA BLAIR CO AP | Apr 23 | May 11 | Apr 8 | Oct 21 | 177 |
| CARLISLE WTP | Apr 23 | May 9 | Apr 9 | Oct 18 | 177 |
| PITTSBURGH INTL AP | Apr 23 | May 12 | Apr 9 | Oct 23 | 181 |
| WILKES-BARRE INTL AP | Apr 23 | May 10 | Apr 9 | Oct 20 | 178 |
| EISENHOWER NHS | Apr 24 | May 10 | Apr 7 | Oct 21 | 180 |
| EMSWORTH L/D OHIO RVR | Apr 24 | May 11 | Apr 9 | Oct 27 | 186 |
| GRATERFORD 1 E | Apr 24 | May 9 | Apr 10 | Oct 15 | 173 |
| HANOVER 4 SW | Apr 24 | May 11 | Apr 9 | Oct 20 | 177 |
| WASHINGTON 3 NE | Apr 24 | May 18 | Apr 8 | Oct 23 | 181 |
| WILLIAMSPORT | Apr 24 | May 11 | Apr 12 | Oct 23 | 180 |
| ALTOONA 3 W | Apr 25 | May 11 | Apr 10 | Oct 21 | 176 |
| ALTOONA 7 SW | Apr 25 | May 14 | Apr 10 | Oct 20 | 177 |
| LAURELTON CTR | Apr 25 | May 11 | Apr 12 | Oct 19 | 175 |
| SELINSGROVE 2 S | Apr 25 | May 10 | Apr 9 | Oct 22 | 178 |
| WILLIAMSPORT 2 | Apr 25 | May 12 | Apr 10 | Oct 24 | 181 |
| BLUE MARSH LAKE | Apr 26 | May 12 | Apr 11 | Oct 19 | 176 |
| ERIE INTL AP | Apr 26 | May 13 | Apr 10 | Nov 4 | 192 |
| LAUREL MTN | Apr 26 | May 13 | Apr 13 | Oct 17 | 172 |
| LEWISBURG | Apr 26 | May 11 | Apr 13 | Oct 20 | 176 |
| OCTORARO LAKE | Apr 26 | May 10 | Apr 9 | Oct 22 | 179 |
| RODALE RSCH CTR | Apr 26 | May 13 | Apr 10 | Oct 14 | 171 |
| SELLERSVILLE | Apr 26 | May 12 | Apr 12 | Oct 17 | 175 |
| W CHESTER 2 NW | Apr 26 | May 11 | Apr 10 | Oct 18 | 174 |
| YORK 3 SSW PUMP STN | Apr 26 | May 13 | Apr 7 | Oct 19 | 177 |
| BEAR GAP | Apr 27 | May 15 | Apr 12 | Oct 20 | 172 |
| BEAVER FALLS 1 NE | Apr 27 | May 16 | Apr 15 | Oct 25 | 178 |
| DONORA 1 SW | Apr 27 | May 15 | Apr 11 | Oct 22 | 177 |
| EVERETT | Apr 27 | May 16 | Apr 12 | Oct 17 | 170 |
| S MTN | Apr 27 | May 14 | Apr 13 | Oct 20 | 177 |
| SELINSGROVE PENN VLY AP | Apr 27 | May 12 | Apr 13 | Oct 16 | 172 |
| YORK AP | Apr 27 | May 11 | Apr 12 | Oct 18 | 174 |
| CASHTOWN 1S | Apr 28 | May 16 | Apr 15 | Oct 17 | 170 |
| GRAYS LANDING | Apr 28 | May 14 | Apr 15 | Oct 21 | 175 |
| MONTGOMERY L&D | Apr 28 | May 15 | Apr 15 | Oct 26 | 178 |
| MOON TWP | Apr 28 | May 15 | Apr 15 | Oct 18 | 172 |
| ALVIN R BUSH DAM | Apr 29 | May 14 | Apr 15 | Oct 21 | 177 |
| BUCKSVILLE | Apr 29 | May 15 | Apr 16 | Oct 16 | 170 |
| JOHNSTOWN CAMBRIA CO AP | Apr 29 | May 17 | Apr 14 | Oct 21 | 176 |
| SALINA 3 W | Apr 29 | May 17 | Apr 14 | Oct 20 | 171 |
| WOLFSBURG | Apr 29 | May 18 | Apr 12 | Oct 13 | 167 |
| CONFLUENCE 1 SW DAM | Apr 30 | May 18 | Apr 17 | Oct 18 | 171 |
| DONEGAL 2 NW | Apr 30 | May 18 | Apr 15 | Oct 17 | 170 |
| LANDISVILLE 2 NW | Apr 30 | May 13 | Apr 16 | Oct 10 | 162 |
| LINESVILLE 1 S | Apr 30 | May 17 | Apr 16 | Oct 23 | 177 |
| LOCK HAVEN SEWAGE PLT | Apr 30 | May 15 | Apr 16 | Oct 20 | 173 |
| MAHANOY CITY 2 N | Apr 30 | May 18 | Apr 15 | Oct 22 | 175 |
| NEW CASTLE 1 N | Apr 30 | May 19 | Apr 17 | Oct 23 | 175 |
| PORT MEADVILLE AP | Apr 30 | May 18 | Apr 16 | Oct 23 | 175 |
| PT MARION LOCK 8 | Apr 30 | May 17 | Apr 14 | Oct 23 | 177 |
| RENOVO | Apr 30 | May 17 | Apr 17 | Oct 22 | 173 |
| SUNBURY | Apr 30 | May 19 | Apr 15 | Oct 13 | 166 |
| UNIONTOWN 1 NE | Apr 30 | May 18 | Apr 15 | Oct 18 | 171 |
| DEHART DAM | May 1 | May 20 | Apr 15 | Oct 16 | 168 |
| E STROUDSBURG | May 1 | May 18 | Apr 18 | Oct 12 | 163 |
| MT PLEASANT | May 1 | May 19 | Apr 17 | Oct 13 | 164 |
| TIONESTA 2 SE LAKE | May 1 | May 18 | Apr 18 | Oct 25 | 176 |
| FRANKLIN | May 2 | May 20 | Apr 20 | Oct 23 | 171 |
| HIDDEN VALLEY | May 2 | May 18 | Apr 19 | Oct 17 | 168 |
| LOYALHANNA LAKE | May 2 | May 18 | Apr 18 | Oct 14 | 163 |
| MATAMORAS | May 2 | May 17 | Apr 20 | Oct 12 | 164 |
| MCKEESPORT | May 2 | May 20 | Apr 17 | Oct 20 | 170 |
| TOWANDA 1 S | May 2 | May 16 | Apr 20 | Oct 15 | 165 |
| MILANVILLE | May 3 | May 21 | Apr 19 | Oct 9 | 156 |
| WAYNESBURG 1 E | May 3 | May 21 | Apr 19 | Oct 15 | 164 |
| BENTON 3 NE | May 4 | May 19 | Apr 21 | Oct 11 | 159 |
| CLEARFIELD LAWRENCE AP | May 4 | May 22 | Apr 19 | Oct 11 | 161 |
| FORD CITY 4 S DAM | May 4 | May 20 | Apr 20 | Oct 16 | 164 |
| GRAMPIAN 1E | May 4 | May 21 | Apr 20 | Oct 13 | 160 |
| JAMESTOWN 2 NW | May 4 | May 22 | Apr 22 | Oct 14 | 161 |
| SHAWNEE SP | May 4 | May 21 | Apr 19 | Oct 10 | 158 |
| WARREN | May 4 | May 22 | Apr 20 | Oct 21 | 168 |
| MILLHEIM | May 5 | May 24 | Apr 22 | Oct 6 | 153 |
| RECTOR 3 SSW | May 5 | May 22 | Apr 21 | Oct 6 | 152 |
| DUBOIS JEFFERSON CO AP | May 6 | May 23 | Apr 19 | Oct 14 | 160 |
| LAPORTE | May 6 | May 22 | Apr 22 | Oct 7 | 154 |
| LAUREL SUMMIT | May 6 | May 23 | Apr 22 | Oct 12 | 159 |
| MT POCONO MOUNTAINS AP | May 6 | May 23 | Apr 21 | Oct 8 | 154 |
| TIOGA HAMMOND DAM | May 6 | May 23 | Apr 24 | Oct 10 | 158 |
| BUTLER 2 SW | May 7 | May 23 | Apr 22 | Oct 14 | 159 |
| EMPORIUM | May 7 | May 23 | Apr 23 | Oct 15 | 160 |
| FRANCIS E WALTER DAM | May 7 | May 23 | Apr 22 | Oct 6 | 153 |
| SLIPPERY ROCK 1 SSW | May 7 | May 25 | Apr 22 | Oct 14 | 158 |
| UNION CITY FILTRATION PLANT | May 7 | May 24 | Apr 23 | Oct 10 | 155 |
| INDIANA 3 SE | May 8 | May 24 | Apr 23 | Oct 13 | 157 |
| SPRINGBORO 3 WNW | May 8 | May 23 | Apr 23 | Oct 16 | 160 |
| CLARION 3 SW | May 9 | May 24 | Apr 24 | Oct 11 | 154 |
| COWANESQUE DAM | May 9 | May 25 | Apr 25 | Oct 12 | 155 |
| HAWLEY 1 E | May 10 | May 26 | Apr 26 | Oct 4 | 146 |
| PRINCE GALLITZIN SP | May 10 | May 28 | Apr 25 | Oct 5 | 149 |
| PUTNEYVILLE 2 SE DAM | May 10 | May 28 | Apr 24 | Oct 12 | 155 |
| STEVENSON DAM | May 10 | May 27 | Apr 25 | Oct 16 | 157 |
| WELLSBORO 4 SW | May 10 | May 26 | Apr 25 | Oct 5 | 148 |
| MEYERSDALE 2 SSW | May 12 | May 28 | Apr 25 | Oct 5 | 146 |
| TITUSVILLE WTR WKS | May 12 | May 28 | Apr 29 | Oct 10 | 149 |
| COOKSBURG 2 NW | May 13 | May 28 | Apr 28 | Oct 7 | 143 |
| PHILIPSBURG 2 S | May 13 | May 29 | Apr 25 | Oct 1 | 142 |
| RIDGWAY | May 13 | May 28 | Apr 26 | Oct 11 | 150 |
| COUDERSPORT 7SE | May 14 | May 30 | Apr 28 | Oct 4 | 143 |
| DUSHORE | May 14 | May 27 | Apr 28 | Oct 2 | 143 |
| GLEN HAZEL 2 NE DAM | May 14 | May 29 | Apr 28 | Oct 6 | 143 |
| MONTROSE | May 14 | May 28 | Apr 29 | Oct 2 | 141 |
| PLEASANT MT 1 W | May 14 | May 29 | Apr 30 | Oct 1 | 140 |
| CLERMONT 1 NW | May 15 | May 31 | Apr 30 | Oct 3 | 140 |
| MERCER | May 15 | Jun 1 | Apr 30 | Oct 3 | 140 |
| PORT ALLEGANY | May 15 | May 29 | Apr 29 | Oct 6 | 144 |
| CANTON | May 16 | May 29 | Apr 27 | Oct 2 | 139 |
| EBENSBURG SEWAGE PLT | May 17 | Jun 1 | Apr 30 | Oct 2 | 136 |
| BRADFORD 4SW RSCH 5 | May 18 | May 31 | Apr 30 | Oct 4 | 140 |
| BRADFORD RGNL AP | May 18 | May 31 | Apr 30 | Oct 1 | 136 |
| CHALK HILL 2 ENE | May 19 | Jun 2 | Apr 30 | Oct 1 | 135 |
| OSWAYO 1 ENE | May 20 | Jun 2 | May 5 | Sep 29 | 130 |
| CLARENCE | May 21 | Jun 1 | Apr 30 | Sep 27 | 130 |
| CHANDLERS VALLEY 1SE | May 22 | Jun 5 | May 6 | Sep 30 | 131 |
| COUDERSPORT 1 SW | May 22 | Jun 6 | May 6 | Oct 1 | 130 |
| KANE 1NNE | May 24 | Jun 7 | May 6 | Sep 28 | 126 |
How to read the three dates
Average is the date by which, in half of the years between 1991 and 2020, the last 32 °F night had already happened. Safe is later: only one year in ten saw a frost after it, which is the date to set out frost-tender plants such as dahlia tubers and zinnia seedlings. Early is the risky end, with a frost after it in nine years out of ten.
Every figure is for the weather station, not for your garden. A valley bottom, a north slope or a spot near a lake can run a week or two either way. Cities are warmer than the countryside around them.
Where the numbers come from
The dates are NOAA's U.S. Climate Normals for 1991 to 2020, computed by the National Centers for Environmental Information for every station with thirty years of daily minimum temperatures. ZIP codes are matched to the nearest such station within 150 km using U.S. Census Bureau ZIP Code Tabulation Area centroids. Stations that never see a frost, such as much of south Florida, report no date and are left out.