Frost dates for Phila Franklin Inst, PA
At Phila Franklin Inst, the median last spring frost (32°F) is Mar 30 and the median first fall frost is Nov 17, for a typical growing season of 232 days. For a 90% chance that the last frost has passed, wait until Apr 12. Nearby ZIP codes are in USDA hardiness zone 7b.
- Mar 30Last spring frost (median)50% chance of 32°F after this date
- Apr 12Safer planting date10% chance of 32°F after this date
- Nov 17First fall frost (median)50% chance of 32°F by this date
- 232 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 | Mar 27 | Apr 8 | Apr 23 |
| 32°F | Mar 15 | Mar 30 | Apr 12 |
| 28°F | Mar 1 | Mar 17 | Mar 31 |
| 24°F | Feb 18 | Mar 8 | Mar 22 |
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 23 | Nov 5 | Nov 20 |
| 32°F | Nov 4 | Nov 17 | Dec 4 |
| 28°F | Nov 12 | Nov 29 | Dec 18 |
| 24°F | Nov 24 | Dec 14 | Jan 2 |
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 | 192 days | 211 days | 230 days |
| 32°F | 214 days | 232 days | 255 days |
| 28°F | 235 days | 257 days | 282 days |
| 24°F | 255 days | 281 days | 305 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 |
|---|---|---|---|
| 19103 | 7b | 5 to 10°F | 1 km |
| 19102 | 7b | 5 to 10°F | 1 km |
| 19130 | 7b | 5 to 10°F | 1 km |
| 19108 | 7b | 5 to 10°F | 1 km |
| 19109 | 7b | 5 to 10°F | 1 km |
| 19107 | 7b | 5 to 10°F | 1 km |
| 19104 | 7b | 5 to 10°F | 2 km |
| 19146 | 7b | 5 to 10°F | 2 km |
| 19123 | 7b | 5 to 10°F | 2 km |
| 19121 | 7b | 5 to 10°F | 3 km |
| 19147 | 7b | 5 to 10°F | 3 km |
| 19106 | 7b | 5 to 10°F | 3 km |
| 19122 | 7b | 5 to 10°F | 3 km |
| 19132 | 7b | 5 to 10°F | 4 km |
| 08102 | 7b | 5 to 10°F | 4 km |
| 19125 | 7b | 5 to 10°F | 5 km |
| 19133 | 7b | 5 to 10°F | 5 km |
| 19143 | 7b | 5 to 10°F | 5 km |
| 19139 | 7b | 5 to 10°F | 5 km |
| 19131 | 7b | 5 to 10°F | 5 km |
| 19145 | 7b | 5 to 10°F | 5 km |
| 19148 | 7b | 5 to 10°F | 6 km |
| 08103 | 7b | 5 to 10°F | 6 km |
| 19129 | 7b | 5 to 10°F | 6 km |
| 19140 | 7b | 5 to 10°F | 6 km |
| 19134 | 7b | 5 to 10°F | 6 km |
| 08104 | 7b | 5 to 10°F | 7 km |
| 19151 | 7b | 5 to 10°F | 8 km |
| 19004 | 7b | 5 to 10°F | 8 km |
| 19050 | 7b | 5 to 10°F | 8 km |
| 19066 | 7b | 5 to 10°F | 8 km |
| 19144 | 7b | 5 to 10°F | 8 km |
| 19082 | 7b | 5 to 10°F | 8 km |
| 08030 | 7b | 5 to 10°F | 9 km |
| 19127 | 7b | 5 to 10°F | 9 km |
| 19141 | 7b | 5 to 10°F | 9 km |
| 19120 | 7b | 5 to 10°F | 10 km |
| 19096 | 7b | 5 to 10°F | 10 km |
| 19072 | 7b | 5 to 10°F | 10 km |
| 19119 | 7b | 5 to 10°F | 11 km |
| 08059 | 7b | 5 to 10°F | 11 km |
| 19138 | 7b | 5 to 10°F | 11 km |
| 19128 | 7b | 5 to 10°F | 11 km |
| 19003 | 7b | 5 to 10°F | 12 km |
| 19083 | 7b | 5 to 10°F | 12 km |
| 19150 | 7b | 5 to 10°F | 13 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 USC00366886, at 39.9586, -75.1728, elevation 18 m (60 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 62.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Philadelphia Intl Airport (11 km)
- Philadelphia NE Airport (19 km)
- Norristown (22 km)
- Marcus Hook (26 km)
- Willow Grove NAS (27 km)
- Neshaminy Falls (28 km)
- Phoenixville 1 E (33 km)
- Graterford 1 E (37 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.