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Pennsylvania Last Frost Date 2027
The average last spring frost (32°F, 50% chance) in Pennsylvania falls between Mar 30 in Delaware County and May 22 in Warren County. The first fall frost comes between Sep 30 (Warren County) and Nov 17 (Philadelphia County).
Photo: Curly kale leaves coated in white frost crystals in a community garden bed. Ruth Hartnup from Vancouver, Canada, CC BY 2.0, via Wikimedia Commons
Frost dates for your Pennsylvania county today
Dates are from the NOAA NCEI U.S. Climate Normals for 1991 to 2020 at the weather station nearest each county center, with the station name, distance and elevation shown. NOAA Climate Normals.
Pennsylvania frost dates at a glance
67 counties, matched to 64 NOAA weather stations. "50% chance" means a freeze happens on or after the spring date, or on or before the fall date, in half of years.
Last and first frost dates for every Pennsylvania county
| County | Zone | Last frost (50%) | Last frost (10%) | First frost (50%) | First frost (10%) | Season days | NOAA station |
|---|---|---|---|---|---|---|---|
| Adams | 7a | Apr 24 | May 10 | Oct 21 | Oct 6 | 180 | Eisenhower Nhs, PA (4 mi) |
| Allegheny | 6b | Apr 24 | May 11 | Oct 27 | Oct 13 | 186 | Emsworth L/D Ohio Rvr, PA (6 mi) |
| Armstrong | 6b | May 4 | May 20 | Oct 16 | Oct 2 | 164 | Ford City 4 S Dam, PA (7 mi) |
| Beaver | 6b | Apr 28 | May 15 | Oct 26 | Oct 9 | 178 | Montgomery L&D, PA (3 mi) |
| Bedford | 6b | Apr 29 | May 18 | Oct 13 | Sep 29 | 167 | Wolfsburg, PA (3 mi) |
| Berks | 7a | Apr 10 | Apr 26 | Oct 31 | Oct 14 | 202 | Reading 4 NNW, PA (1 mi) |
| Blair | 6b | Apr 25 | May 14 | Oct 20 | Oct 6 | 177 | Altoona 7 SW, PA (8 mi) |
| Bradford | 6a | May 2 | May 16 | Oct 15 | Oct 1 | 165 | Towanda 1 S, PA (4 mi) |
| Bucks | 7a | Apr 13 | Apr 27 | Oct 30 | Oct 15 | 198 | Doylestown Airport, PA (1 mi) |
| Butler | 6a | May 7 | May 23 | Oct 14 | Oct 1 | 159 | Butler 2 SW, PA (5 mi) |
| Cambria | 6a | May 17 | Jun 1 | Oct 2 | Sep 19 | 136 | Ebensburg Sewage Plt, PA (3 mi) |
| Cameron | 5b | May 7 | May 23 | Oct 15 | Oct 1 | 160 | Emporium, PA (5 mi) |
| Carbon | 6b | May 7 | May 23 | Oct 6 | Sep 22 | 153 | Francis E Walter Dam, PA (14 mi) |
| Centre | 6b | Apr 20 | May 6 | Oct 26 | Oct 10 | 187 | State College, PA (8 mi) |
| Chester | 7a | Apr 19 | May 4 | Oct 25 | Oct 11 | 190 | Coatesville 2 W, PA (6 mi) |
| Clarion | 6a | May 9 | May 24 | Oct 11 | Sep 30 | 154 | Clarion 3 SW, PA (1 mi) |
| Clearfield | 6a | May 4 | May 22 | Oct 11 | Sep 29 | 161 | Clearfield Lawrence Airport, PA (4 mi) |
| Clinton | 6a | Apr 30 | May 17 | Oct 22 | Oct 6 | 173 | Renovo, PA (8 mi) |
| Columbia | 6b | May 4 | May 19 | Oct 11 | Sep 29 | 159 | Benton 3 NE, PA (13 mi) |
| Crawford | 6a | Apr 30 | May 18 | Oct 23 | Oct 6 | 175 | Port Meadville Airport, PA (7 mi) |
| Cumberland | 7a | Apr 23 | May 9 | Oct 18 | Oct 4 | 177 | Carlisle Wtp, PA (6 mi) |
| Dauphin | 7a | May 1 | May 20 | Oct 16 | Oct 3 | 168 | Dehart Dam, PA (4 mi) |
| Delaware | 7b | Mar 30 | Apr 9 | Nov 16 | Nov 2 | 230 | Marcus Hook, PA (7 mi) |
| Elk | 5b | May 13 | May 28 | Oct 11 | Sep 28 | 150 | Ridgway, PA (5 mi) |
| Erie | 6a | Apr 26 | May 13 | Nov 4 | Oct 21 | 192 | Erie Intl Airport, PA (5 mi) |
| Fayette | 6b | Apr 30 | May 18 | Oct 18 | Oct 5 | 171 | Uniontown 1 NE, PA (4 mi) |
| Forest | 6a | May 1 | May 18 | Oct 25 | Oct 8 | 176 | Tionesta 2 SE Lake, PA (10 mi) |
| Franklin | 7a | Apr 18 | May 5 | Oct 25 | Oct 10 | 188 | Chambersburg 1 ESE, PA (5 mi) |
| Fulton | 7a | Apr 27 | May 16 | Oct 17 | Oct 3 | 170 | Everett, PA (15 mi) |
| Greene | 6b | May 3 | May 21 | Oct 15 | Oct 2 | 164 | Waynesburg 1 E, PA (5 mi) |
| Huntingdon | 6b | Apr 19 | May 7 | Oct 28 | Oct 12 | 191 | Raystown Lake 2, PA (6 mi) |
| Indiana | 6b | May 8 | May 24 | Oct 13 | Oct 1 | 157 | Indiana 3 SE, PA (4 mi) |
| Jefferson | 6a | May 6 | May 23 | Oct 14 | Sep 29 | 160 | Dubois Jefferson Co Airport, PA (7 mi) |
| Juniata | 7a | Apr 21 | May 9 | Oct 24 | Oct 7 | 185 | Lewistown, PA (10 mi) |
| Lackawanna | 6a | Apr 23 | May 10 | Oct 20 | Oct 4 | 178 | Wilkes-Barre Intl Airport, PA (9 mi) |
| Lancaster | 7a | Apr 19 | May 7 | Oct 24 | Oct 9 | 186 | Lancaster 2Ne Fltr Plt, PA (1 mi) |
| Lawrence | 6a | Apr 30 | May 19 | Oct 23 | Oct 6 | 175 | New Castle 1 N, PA (2 mi) |
| Lebanon | 7a | Apr 20 | May 7 | Oct 25 | Oct 10 | 185 | Lebanon 2 W, PA (3 mi) |
| Lehigh | 7a | Apr 20 | May 6 | Oct 24 | Oct 8 | 184 | Allentown Intl Airport, PA (8 mi) |
| Luzerne | 6b | May 7 | May 23 | Oct 6 | Sep 22 | 153 | Francis E Walter Dam, PA (13 mi) |
| Lycoming | 6a | Apr 25 | May 12 | Oct 24 | Oct 8 | 181 | Williamsport 2, PA (8 mi) |
| McKean | 5b | May 18 | May 31 | Oct 1 | Sep 18 | 136 | Bradford Rgnl Airport, PA (4 mi) |
| Mercer | 6a | May 15 | Jun 1 | Oct 3 | Sep 19 | 140 | Mercer, PA (5 mi) |
| Mifflin | 6b | Apr 21 | May 9 | Oct 24 | Oct 7 | 185 | Lewistown, PA (4 mi) |
| Monroe | 6b | May 6 | May 23 | Oct 8 | Sep 27 | 154 | Mt Pocono Mountains Airport, PA (6 mi) |
| Montgomery | 7a | Apr 24 | May 9 | Oct 15 | Oct 1 | 173 | Graterford 1 E, PA (3 mi) |
| Montour | 6b | Apr 26 | May 11 | Oct 20 | Oct 5 | 176 | Lewisburg, PA (12 mi) |
| Northampton | 7a | Apr 18 | May 5 | Oct 25 | Oct 11 | 188 | Phillipsburg-Easton Brg, NJ (7 mi) |
| Northumberland | 6b | Apr 30 | May 19 | Oct 13 | Sep 30 | 166 | Sunbury, PA (4 mi) |
| Perry | 7a | Apr 18 | May 8 | Oct 26 | Oct 11 | 191 | Bloserville 1 N, PA (11 mi) |
| Philadelphia | 7b | Mar 30 | Apr 12 | Nov 17 | Nov 4 | 232 | Phila Franklin Inst, PA (4 mi) |
| Pike | 6a | May 10 | May 26 | Oct 4 | Sep 21 | 146 | Hawley 1 E, PA (12 mi) |
| Potter | 5b | May 14 | May 30 | Oct 4 | Sep 21 | 143 | Coudersport 7Se, PA (4 mi) |
| Schuylkill | 6b | Apr 30 | May 18 | Oct 22 | Oct 7 | 175 | Mahanoy City 2 N, PA (10 mi) |
| Snyder | 6b | Apr 25 | May 10 | Oct 22 | Oct 7 | 178 | Selinsgrove 2 S, PA (11 mi) |
| Somerset | 6a | May 12 | May 28 | Oct 5 | Sep 24 | 146 | Meyersdale 2 SSW, PA (14 mi) |
| Sullivan | 6a | May 6 | May 22 | Oct 7 | Sep 24 | 154 | Laporte, PA (1 mi) |
| Susquehanna | 5b | May 14 | May 28 | Oct 2 | Sep 20 | 141 | Montrose, PA (4 mi) |
| Tioga | 6a | May 10 | May 26 | Oct 5 | Sep 23 | 148 | Wellsboro 4 SW, PA (8 mi) |
| Union | 6b | Apr 25 | May 11 | Oct 19 | Oct 4 | 175 | Laurelton Ctr, PA (9 mi) |
| Venango | 6a | May 2 | May 20 | Oct 23 | Oct 8 | 171 | Franklin, PA (3 mi) |
| Warren | 6a | May 22 | Jun 5 | Sep 30 | Sep 16 | 131 | Chandlers Valley 1Se, PA (7 mi) |
| Washington | 6b | Apr 24 | May 18 | Oct 23 | Oct 8 | 181 | Washington 3 NE, PA (4 mi) |
| Wayne | 6a | May 14 | May 29 | Oct 1 | Sep 21 | 140 | Pleasant Mt 1 W, PA (10 mi) |
| Westmoreland | 6b | May 1 | May 19 | Oct 13 | Oct 3 | 164 | Mt Pleasant, PA (7 mi) |
| Wyoming | 6a | Apr 23 | May 10 | Oct 20 | Oct 4 | 178 | Wilkes-Barre Intl Airport, PA (20 mi) |
| York | 7a | Apr 26 | May 13 | Oct 19 | Oct 5 | 177 | York 3 SSW Pump Stn, PA (1 mi) |
10% columns: a freeze after the spring date, or before the fall date, happens in about 1 year in 10. Zones are USDA 2023 Plant Hardiness Zones.
When to plant in Pennsylvania: crop by crop
Planting dates for each crop in Pennsylvania, from the Penn State Extension calendar.
Pennsylvania frost date questions
When is the last frost in Pennsylvania?
The average last spring frost (32°F, 50% chance) in Pennsylvania falls between Mar 30 in Delaware County and May 22 in Warren County. The first fall frost comes between Sep 30 (Warren County) and Nov 17 (Philadelphia County).
What does a 50% last frost date mean?
In half of the years from 1991 to 2020, the last 32°F night came on or after that date. Waiting until the 10% date cuts the risk to about 1 year in 10.
When is it safe to plant tomatoes in Pennsylvania?
Tender crops such as tomatoes and peppers go out after the last frost. Use the 10% date for your county for a safer margin; the Penn State Extension planting calendar has the crop dates.
When is the first frost in Pennsylvania?
The 50% first fall frost ranges from Sep 30 in Warren County to Nov 17 in Philadelphia County.
How long is the growing season in Pennsylvania?
Between 131 days (Warren County) and 232 days (Philadelphia County) between the last and first 32°F freeze in half of years.
What is the difference between frost and a hard freeze?
These dates use 32°F, when tender plants are damaged. A 28°F hard freeze damages most hardy vegetables; the widget shows both.
Where do these frost dates come from?
NOAA NCEI U.S. Climate Normals for 1991 to 2020, freeze probability dates for each weather station. Each county uses its nearest station with a complete record.
Why does my county use a station in another county?
Not every county has a NOAA station with a full 30-year record. The station name, distance and elevation are listed so you can judge how close it is to your garden.
Photos: Curly kale leaves coated in white frost crystals in a community garden bed: Ruth Hartnup from Vancouver, Canada, CC BY 2.0, via Wikimedia Commons; Farmstead on a glacial drumlin among autumn woods in Washington Township, Erie County: Nicholas A. Tonelli, CC BY 2.0, via Flickr; Farmstead with silo and red barns below an autumn ridge in Nippenose Valley, Clinton County: Nicholas A. Tonelli, CC BY 2.0, via Flickr; Sugar Valley farms below an autumn mountainside, Clinton County: Nicholas A. Tonelli, CC BY 2.0, via Flickr; Farmstead and cornfields under a wooded mountain in Sugar Valley, Clinton County: Nicholas A. Tonelli, CC BY 2.0, via Flickr; Staked tomato plant in a straw-mulched kitchen garden with green and ripening red tomatoes: NPS, Public domain, via Wikimedia Commons; Pepper plant in a kitchen garden loaded with green, yellow and red peppers: NPS, Public domain, via Wikimedia Commons; Potato plants growing in a home garden: Geo Lightspeed7, CC BY-SA 4.0, via Wikimedia Commons; Rows of sweet corn in a field: Wee Hong, CC BY-SA 4.0, via Wikimedia Commons; Clusters of long green bean pods hanging from a climbing bean vine: Nirajan_pant, CC BY-SA 3.0, via Wikimedia Commons; Cucumber plants growing in a greenhouse bed: HARTLEPOOLMARINA2014, CC BY-SA 4.0, via Wikimedia Commons; Zucchini plant with a yellow flower: net_efekt from Oxford, UK, CC BY 2.0, via Wikimedia Commons; Green and red leaf lettuce heads growing along drip lines in a garden bed: Forest and Kim Starr, CC BY 3.0 US, via Wikimedia Commons; Long rows of green onion plants growing in sandy farm soil: ליזי שאנן, CC BY 2.5, via Wikimedia Commons; Neat rows of young garlic shoots growing in dark tilled soil: Timothy A. Gonsalves, CC BY-SA 4.0, via Wikimedia Commons; Pea plants growing up supports in a garden: Kolforn (Kolforn), CC BY-SA 4.0, via Wikimedia Commons; Young watermelon plant in a garden: Forest and Kim Starr, CC BY 3.0 us, via Wikimedia Commons.