Pennsylvania Frost Dates: Last and First Frost by Town

160 NOAA weather stations · 1991–2020 U.S. Climate Normals · Data updated 2026-10-29

Quick answer

Across Pennsylvania's 160 NOAA stations with regular frost, the median last spring frost is April 29 and the median first fall frost is October 20. Last frost dates range from March 30 at Marcus Hook to May 24 at Kane 1NNE, so enter your ZIP code below for the station nearest you.

How frost dates vary across Pennsylvania

Elevation matters: across Pennsylvania's stations, each 1,000 ft of elevation delays the median last frost by about 13 days.
North vs south: stations in the northern third of the state (north of 41.0°N) reach their median last frost about 13 days later than the southern third (south of 40.2°N).
Safety margin: the median 10%-risk date (May 16) is about 17 days after the median last frost. Waiting until then cuts the chance of a killing frost on tender transplants from 1 in 2 to 1 in 10.

Frost dates at Pennsylvania's major weather stations

These National Weather Service stations, mostly at airports, have the longest and most complete records in the state.


Allentown Intl Airport	390	Apr 20	May 6	Oct 24	184
Altoona Blair County Airport	1,480	Apr 23	May 11	Oct 21	177
Avondale 2 N	400	Apr 19	May 3	Oct 26	189
Bradford Regional Airport	2,117	May 18	May 31	Oct 1	136
Clearfield Lawrence Airport	1,516	May 4	May 22	Oct 11	161
Doylestown Airport	394	Apr 13	Apr 27	Oct 30	198
Dubois Jefferson County Airport	1,814	May 6	May 23	Oct 14	160
Erie Intl Airport	730	Apr 26	May 13	Nov 4	192
Harrisburg Cptl Cy Airport	340	Apr 9	Apr 25	Nov 1	205
Johnstown Cambria County Airport	2,284	Apr 29	May 17	Oct 21	176
Lancaster Airport	403	Apr 18	May 5	Oct 25	186
Middletown Harrisburg Intl Airport	312	Apr 9	Apr 25	Nov 2	206
Mount Pocono Mountains Airport	1,916	May 6	May 23	Oct 8	154
Philadelphia Intl Airport	10	Apr 2	Apr 13	Nov 10	224
Philadelphia NE Airport	100	Apr 4	Apr 17	Nov 7	216
Pittsburgh Allegheny County Airport	1,248	Apr 18	May 6	Oct 28	193
Pittsburgh Intl Airport	1,203	Apr 23	May 12	Oct 23	181
Port Meadville Airport	1,400	Apr 30	May 18	Oct 23	175
Pottstown Limerick Airport	291	Apr 20	May 6	Oct 23	186
Reading Spaatz Field	341	Apr 14	Apr 30	Oct 29	197
Selinsgrove Penn Valley Airport	444	Apr 27	May 12	Oct 16	172
Wilkes-barre Intl Airport	930	Apr 23	May 10	Oct 20	178
Williamsport	520	Apr 24	May 11	Oct 23	180
Willow Grove NAS	361	Apr 11	Apr 27	Nov 1	205
York Airport	486	Apr 27	May 11	Oct 18	174

All 160 stations in Pennsylvania

Last frost and first frost are medians: a 50% chance of a 32°F night after (spring) or before (fall) that date. 10% risk is the spring date with only a 1-in-10 chance of a later frost. Click a column to sort.

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Acmetonia Lock 3	748	Apr 16	May 4	Nov 1	197
Allentown Intl Airport	390	Apr 20	May 6	Oct 24	184
Altoona 3 W	1,320	Apr 25	May 11	Oct 21	176
Altoona 7 SW	1,180	Apr 25	May 14	Oct 20	177
Altoona Blair County Airport	1,480	Apr 23	May 11	Oct 21	177
Alvin R Bush Dam	930	Apr 29	May 14	Oct 21	177
Avondale 2 N	400	Apr 19	May 3	Oct 26	189
Bear Gap	1,015	Apr 27	May 15	Oct 20	172
Beaver Falls 1 NE	760	Apr 27	May 16	Oct 25	178
Benton 3 NE	1,095	May 4	May 19	Oct 11	159
Biglerville	720	Apr 15	May 4	Oct 27	194
Bloserville 1 N	700	Apr 18	May 8	Oct 26	191
Blue Marsh Lake	350	Apr 26	May 12	Oct 19	176
Braddock Lock 2	730	Apr 5	Apr 22	Nov 10	219
Bradford 4SW Rsch 5	1,660	May 18	May 31	Oct 4	140
Bradford Regional Airport	2,117	May 18	May 31	Oct 1	136
Bucksville	387	Apr 29	May 15	Oct 16	170
Butler 2 SW	1,000	May 7	May 23	Oct 14	159
Canton	1,140	May 16	May 29	Oct 2	139
Carlisle Wtp	430	Apr 23	May 9	Oct 18	177
Cashtown 1S	710	Apr 28	May 16	Oct 17	170
Chalk Hill 2 ENE	1,980	May 19	Jun 2	Oct 1	135
Chambersburg 1 ESE	640	Apr 18	May 5	Oct 25	188
Chandlers Valley 1SE	1,490	May 22	Jun 5	Sep 30	131
Charleroi Lock 4	749	Apr 13	May 5	Nov 5	205
Clarence	1,390	May 21	Jun 1	Sep 27	130
Clarion 3 SW	1,040	May 9	May 24	Oct 11	154
Clearfield Lawrence Airport	1,516	May 4	May 22	Oct 11	161
Clermont 1 NW	2,080	May 15	May 31	Oct 3	140
Coatesville 2 W	640	Apr 19	May 4	Oct 25	190
Confluence 1 SW Dam	1,490	Apr 30	May 18	Oct 18	171
Connellsville 2 SSW	900	Apr 22	May 11	Oct 27	187
Cooksburg 2 NW	1,450	May 13	May 28	Oct 7	143
Coudersport 1 SW	1,650	May 22	Jun 6	Oct 1	130
Coudersport 7SE	2,150	May 14	May 30	Oct 4	143
Cowanesque Dam	1,150	May 9	May 25	Oct 12	155
Dehart Dam	537	May 1	May 20	Oct 16	168
Donegal 2 NW	1,800	Apr 30	May 18	Oct 17	170
Donora 1 SW	762	Apr 27	May 15	Oct 22	177
Doylestown Airport	394	Apr 13	Apr 27	Oct 30	198
Dubois Jefferson County Airport	1,814	May 6	May 23	Oct 14	160
Dushore	1,530	May 14	May 27	Oct 2	143
E Stroudsburg	471	May 1	May 18	Oct 12	163
Ebensburg Sewage Plt	1,940	May 17	Jun 1	Oct 2	136
Eisenhower Nhs	540	Apr 24	May 10	Oct 21	180
Emporium	1,040	May 7	May 23	Oct 15	160
Emsworth L/d Ohio River	717	Apr 24	May 11	Oct 27	186
Erie Intl Airport	730	Apr 26	May 13	Nov 4	192
Everett	1,000	Apr 27	May 16	Oct 17	170
Ford City 4 S Dam	930	May 4	May 20	Oct 16	164
Francis E Walter Dam	1,509	May 7	May 23	Oct 6	153
Franklin	1,015	May 2	May 20	Oct 23	171
Glen Hazel 2 NE Dam	1,720	May 14	May 29	Oct 6	143
Glenmoore	500	Apr 11	Apr 29	Nov 1	205
Glenwillard Dashields L&d	710	Apr 8	Apr 26	Nov 8	212
Grampian 1E	1,510	May 4	May 21	Oct 13	160
Graterford 1 E	279	Apr 24	May 9	Oct 15	173
Grays Landing	800	Apr 28	May 14	Oct 21	175
Hamburg	369	Apr 16	May 3	Oct 25	189
Hanover 4 SW	558	Apr 24	May 11	Oct 20	177
Harrisburg 1 NE	420	Apr 15	May 2	Oct 23	189
Harrisburg Cptl Cy Airport	340	Apr 9	Apr 25	Nov 1	205
Hawley 1 E	890	May 10	May 26	Oct 4	146
Hidden Valley	2,876	May 2	May 18	Oct 17	168
Hopewell Morgantown	550	Apr 16	Apr 30	Oct 27	193
Indiana 3 SE	1,102	May 8	May 24	Oct 13	157
Jamestown 2 NW	1,040	May 4	May 22	Oct 14	161
Johnstown Cambria County Airport	2,284	Apr 29	May 17	Oct 21	176
Kane 1NNE	1,750	May 24	Jun 7	Sep 28	126
Lancaster 2NE Fltr Plt	270	Apr 19	May 7	Oct 24	186
Lancaster Airport	403	Apr 18	May 5	Oct 25	186
Landisville 2 NW	360	Apr 30	May 13	Oct 10	162
Laporte	1,966	May 6	May 22	Oct 7	154
Laurel Mountain	2,760	Apr 26	May 13	Oct 17	172
Laurel Summit	2,730	May 6	May 23	Oct 12	159
Laurelton Center	800	Apr 25	May 11	Oct 19	175
Lebanon 2 W	450	Apr 20	May 7	Oct 25	185
Lehighton 1SSW	455	Apr 21	May 9	Oct 23	184
Lewisburg	500	Apr 26	May 11	Oct 20	176
Lewistown	460	Apr 21	May 9	Oct 24	185
Linesville 1 S	1,030	Apr 30	May 17	Oct 23	177
Lock Haven Sewage Plt	566	Apr 30	May 15	Oct 20	173
Loyalhanna Lake	990	May 2	May 18	Oct 14	163
Mahanoy City 2 N	1,710	Apr 30	May 18	Oct 22	175
Marcus Hook	10	Mar 30	Apr 9	Nov 16	230
Matamoras	459	May 2	May 17	Oct 12	164
McKeesport	740	May 2	May 20	Oct 20	170
Mercer	1,220	May 15	Jun 1	Oct 3	140
Meyersdale 2 SSW	2,000	May 12	May 28	Oct 5	146
Middletown Harrisburg Intl Airport	312	Apr 9	Apr 25	Nov 2	206
Milanville	760	May 3	May 21	Oct 9	156
Millheim	1,120	May 5	May 24	Oct 6	153
Montgomery L&d	690	Apr 28	May 15	Oct 26	178
Montrose	1,420	May 14	May 28	Oct 2	141
Moon Twp	1,172	Apr 28	May 15	Oct 18	172
Mount Pleasant	1,003	May 1	May 19	Oct 13	164
Mount Pocono Mountains Airport	1,916	May 6	May 23	Oct 8	154
Murrysville 2 SW	860	Apr 22	May 12	Oct 25	186
Natrona Lock 4	760	Apr 16	May 2	Nov 2	199
Neshaminy Falls	40	Apr 21	May 7	Oct 25	185
New Castle 1 N	825	Apr 30	May 19	Oct 23	175
New Holland 2 SE	605	Apr 14	Apr 30	Nov 1	198
Norristown	62	Apr 8	Apr 23	Oct 31	203
Octoraro Lake	260	Apr 26	May 10	Oct 22	179
Oswayo 1 ENE	1,710	May 20	Jun 2	Sep 29	130
Phila Franklin Inst	60	Mar 30	Apr 12	Nov 17	232
Philadelphia Intl Airport	10	Apr 2	Apr 13	Nov 10	224
Philadelphia NE Airport	100	Apr 4	Apr 17	Nov 7	216
Philipsburg 2 S	1,720	May 13	May 29	Oct 1	142
Phoenixville 1 E	85	Apr 18	May 4	Oct 27	192
Pittsburgh Allegheny County Airport	1,248	Apr 18	May 6	Oct 28	193
Pittsburgh Intl Airport	1,203	Apr 23	May 12	Oct 23	181
Pleasant Mount 1 W	1,800	May 14	May 29	Oct 1	140
Point Marion Lock 8	810	Apr 30	May 17	Oct 23	177
Port Allegany	1,475	May 15	May 29	Oct 6	144
Port Meadville Airport	1,400	Apr 30	May 18	Oct 23	175
Pottstown Limerick Airport	291	Apr 20	May 6	Oct 23	186
Prince Gallitzin State Park	1,520	May 10	May 28	Oct 5	149
Putneyville 2 SE Dam	1,280	May 10	May 28	Oct 12	155
Raystown HQ	995	Apr 19	May 8	Oct 29	194
Raystown Lake 2	1,000	Apr 19	May 7	Oct 28	191
Reading 4 NNW	360	Apr 10	Apr 26	Oct 31	202
Reading Spaatz Field	341	Apr 14	Apr 30	Oct 29	197
Rector 3 SSW	1,330	May 5	May 22	Oct 6	152
Renovo	660	Apr 30	May 17	Oct 22	173
Ridgway	1,360	May 13	May 28	Oct 11	150
Rodale Rsch Center	550	Apr 26	May 13	Oct 14	171
S Mountain	1,520	Apr 27	May 14	Oct 20	177
Safe Harbor Dam	195	Apr 1	Apr 13	Nov 10	221
Salina 3 W	1,109	Apr 29	May 17	Oct 20	171
Schenley Lock 5	783	Apr 21	May 9	Oct 30	190
Selinsgrove 2 S	420	Apr 25	May 10	Oct 22	178
Selinsgrove Penn Valley Airport	444	Apr 27	May 12	Oct 16	172
Sellersville	302	Apr 26	May 12	Oct 17	175
Shawnee State Park	1,275	May 4	May 21	Oct 10	158
Shippensburg	680	Apr 19	May 6	Oct 24	188
Slippery Rock 1 SSW	1,260	May 7	May 25	Oct 14	158
Springboro 3 WNW	1,005	May 8	May 23	Oct 16	160
Springtown 1 NNE	860	Apr 21	May 6	Oct 22	184
State College	1,170	Apr 20	May 6	Oct 26	187
Stevenson Dam	932	May 10	May 27	Oct 16	157
Sunbury	575	Apr 30	May 19	Oct 13	166
Tioga Hammond Dam	1,230	May 6	May 23	Oct 10	158
Tionesta 2 SE Lake	1,200	May 1	May 18	Oct 25	176
Titusville Wtr Wks	1,220	May 12	May 28	Oct 10	149
Towanda 1 S	760	May 2	May 16	Oct 15	165
Union City Filtration Plant	1,400	May 7	May 24	Oct 10	155
Uniontown 1 NE	956	Apr 30	May 18	Oct 18	171
W Chester 2 NW	375	Apr 26	May 11	Oct 18	174
Warren	1,210	May 4	May 22	Oct 21	168
Washington 3 NE	1,300	Apr 24	May 18	Oct 23	181
Waynesburg 1 E	940	May 3	May 21	Oct 15	164
Wellsboro 4 SW	1,818	May 10	May 26	Oct 5	148
Wilkes-barre Intl Airport	930	Apr 23	May 10	Oct 20	178
Williamsport	520	Apr 24	May 11	Oct 23	180
Williamsport 2	525	Apr 25	May 12	Oct 24	181
Willow Grove NAS	361	Apr 11	Apr 27	Nov 1	205
Wolfsburg	1,185	Apr 29	May 18	Oct 13	167
York 3 SSW Pump Station	390	Apr 26	May 13	Oct 19	177
York Airport	486	Apr 27	May 11	Oct 18	174

Frequently asked questions

When is the last frost in Pennsylvania?

The median last spring frost (32°F) across Pennsylvania's NOAA weather stations is April 29, based on 1991–2020 climate normals. It ranges from March 30 at Marcus Hook to May 24 at Kane 1NNE. For a safer planting date, use the 10%-risk date; the state median for that is May 16.

When is the first frost in Pennsylvania?

The median first fall frost across Pennsylvania's stations is October 20. The earliest median first frost is September 27 at Clarence, and the latest is November 17 at Phila Franklin Inst.

How long is the growing season in Pennsylvania?

The median frost-free season is 174 days across Pennsylvania's stations, from 126 days at Kane 1NNE to 232 days at Phila Franklin Inst.

When should I plant tomatoes in Pennsylvania?

Plant tomatoes outdoors after your local last frost, ideally after the 10%-risk date when nights stay above 50°F. At a typical Pennsylvania station that means starting seeds indoors 6–8 weeks before April 29 and transplanting from about May 16. Check your ZIP code, because dates vary by weeks across the state.

How to use these dates

Frost dates are 30-year averages from NOAA, not forecasts. Use them to plan seed starting and planting, then watch the 10-day forecast as the date approaches. Cold air settles in valleys and low spots, so a garden at the bottom of a slope can frost a week or more later in spring than the nearest station shows.

Ready to plan? The planting calendar by ZIP code turns these dates into start-indoors, transplant and sowing dates for 30 crops.

Sources and method

Dates are the 32°F freeze probabilities published in the NOAA NCEI 1991–2020 U.S. Climate Normals for each station. Station names are NOAA's, lightly expanded for readability. See the methodology or download the full table.