Frost dates for Philadelphia Intl Airport, PA
At Philadelphia Intl Airport, the median last spring frost (32°F) is Apr 2 and the median first fall frost is Nov 10, for a typical growing season of 224 days. For a 90% chance that the last frost has passed, wait until Apr 13. Nearby ZIP codes are in USDA hardiness zones 7b to 8a.
- Apr 2Last spring frost (median)50% chance of 32°F after this date
- Apr 13Safer planting date10% chance of 32°F after this date
- Nov 10First fall frost (median)50% chance of 32°F by this date
- 224 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 1 | Apr 13 | Apr 28 |
| 32°F | Mar 19 | Apr 2 | Apr 13 |
| 28°F | Mar 7 | Mar 22 | Apr 3 |
| 24°F | Feb 24 | Mar 12 | Mar 26 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 18 | Oct 31 | Nov 12 |
| 32°F | Oct 30 | Nov 10 | Nov 24 |
| 28°F | Nov 7 | Nov 23 | Dec 8 |
| 24°F | Nov 17 | Dec 4 | Dec 23 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 182 days | 200 days | 219 days |
| 32°F | 207 days | 224 days | 243 days |
| 28°F | 227 days | 246 days | 269 days |
| 24°F | 245 days | 269 days | 293 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 19153 | 7b | 5 to 10°F | 1 km |
| 19113 | 7b | 5 to 10°F | 4 km |
| 08066 | 7b | 5 to 10°F | 4 km |
| 08063 | 7b | 5 to 10°F | 4 km |
| 08086 | 7b | 5 to 10°F | 4 km |
| 19032 | 7b | 5 to 10°F | 4 km |
| 19079 | 7b | 5 to 10°F | 5 km |
| 19029 | 7b | 5 to 10°F | 5 km |
| 19112 | 7b | 5 to 10°F | 6 km |
| 19074 | 7b | 5 to 10°F | 6 km |
| 19142 | 7b | 5 to 10°F | 6 km |
| 19023 | 7b | 5 to 10°F | 6 km |
| 19036 | 7b | 5 to 10°F | 7 km |
| 19076 | 7b | 5 to 10°F | 7 km |
| 08027 | 7b | 5 to 10°F | 7 km |
| 19043 | 7b | 5 to 10°F | 8 km |
| 19078 | 8a | 10 to 15°F | 8 km |
| 08061 | 7b | 5 to 10°F | 8 km |
| 08020 | 7b | 5 to 10°F | 8 km |
| 19018 | 7b | 5 to 10°F | 8 km |
| 08093 | 7b | 5 to 10°F | 8 km |
| 19033 | 7b | 5 to 10°F | 9 km |
| 19070 | 7b | 5 to 10°F | 9 km |
| 08097 | 7b | 5 to 10°F | 9 km |
| 08056 | 7b | 5 to 10°F | 10 km |
| 08096 | 7b | 5 to 10°F | 10 km |
| 19081 | 7b | 5 to 10°F | 10 km |
| 19026 | 7b | 5 to 10°F | 11 km |
| 19064 | 7b | 5 to 10°F | 12 km |
| 08031 | 7b | 5 to 10°F | 12 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00013739, at 39.8683, -75.2311, elevation 3 m (10 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 77.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Phila Franklin Inst (11 km)
- Marcus Hook (18 km)
- Norristown (28 km)
- Philadelphia NE Airport (30 km)
- Phoenixville 1 E (36 km)
- W Chester 2 NW (36 km)
- Willow Grove NAS (38 km)
- Neshaminy Falls (39 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.