Frost dates for Philadelphia/mt Holly WFO, NJ
At Philadelphia/mt Holly WFO, the median last spring frost (32°F) is Apr 15 and the median first fall frost is Oct 29, for a typical growing season of 196 days. For a 90% chance that the last frost has passed, wait until Apr 29. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- Apr 15Last spring frost (median)50% chance of 32°F after this date
- Apr 29Safer planting date10% chance of 32°F after this date
- Oct 29First fall frost (median)50% chance of 32°F by this date
- 196 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 15 | Apr 28 | May 13 |
| 32°F | Apr 1 | Apr 15 | Apr 29 |
| 28°F | Mar 18 | Apr 1 | Apr 15 |
| 24°F | Mar 5 | Mar 20 | Apr 3 |
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 4 | Oct 17 | Oct 31 |
| 32°F | Oct 14 | Oct 29 | Nov 10 |
| 28°F | Oct 26 | Nov 7 | Nov 21 |
| 24°F | Nov 4 | Nov 18 | Dec 5 |
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 | 152 days | 172 days | 191 days |
| 32°F | 176 days | 196 days | 214 days |
| 28°F | 200 days | 218 days | 238 days |
| 24°F | 222 days | 243 days | 265 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 |
|---|---|---|---|
| 08060 | 7b | 5 to 10°F | 2 km |
| 08073 | 7b | 5 to 10°F | 4 km |
| 08046 | 7b | 5 to 10°F | 6 km |
| 08016 | 7b | 5 to 10°F | 6 km |
| 08011 | 7b | 5 to 10°F | 10 km |
| 08022 | 7a | 0 to 5°F | 11 km |
| 08518 | 7b | 5 to 10°F | 11 km |
| 08554 | 7a | 0 to 5°F | 11 km |
| 08041 | 7b | 5 to 10°F | 12 km |
| 08042 | 7b | 5 to 10°F | 13 km |
| 08068 | 7a | 0 to 5°F | 14 km |
| 08505 | 7a | 0 to 5°F | 16 km |
| 08515 | 7a | 0 to 5°F | 18 km |
| 08064 | 7a | 0 to 5°F | 19 km |
| 08641 | 7a | 0 to 5°F | 20 km |
| 08562 | 7a | 0 to 5°F | 20 km |
| 08640 | 7a | 0 to 5°F | 21 km |
| 08511 | 7a | 0 to 5°F | 23 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 USC00286964, at 40.0136, -74.8175, elevation 19 m (63 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 111.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mount Holly S Jersey Airport (7 km)
- Moorestown (15 km)
- Pennsauken 1n (18 km)
- Indian Mills 2 W (24 km)
- Trenton State College (29 km)
- Trenton Mercer Co Airport (29 km)
- Hightstown 2 W (35 km)
- Glassboro 2 NE (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.