Frost dates for Reading 4 NNW, PA
At Reading 4 NNW, the median last spring frost (32°F) is Apr 10 and the median first fall frost is Oct 31, for a typical growing season of 202 days. For a 90% chance that the last frost has passed, wait until Apr 26. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 10Last spring frost (median)50% chance of 32°F after this date
- Apr 26Safer planting date10% chance of 32°F after this date
- Oct 31First fall frost (median)50% chance of 32°F by this date
- 202 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 9 | Apr 25 | May 9 |
| 32°F | Mar 29 | Apr 10 | Apr 26 |
| 28°F | Mar 15 | Mar 30 | Apr 12 |
| 24°F | Mar 4 | Mar 19 | Apr 1 |
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 3 | Oct 18 | Nov 2 |
| 32°F | Oct 14 | Oct 31 | Nov 13 |
| 28°F | Oct 27 | Nov 11 | Nov 28 |
| 24°F | Nov 9 | Nov 24 | Dec 12 |
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 | 156 days | 177 days | 198 days |
| 32°F | 181 days | 202 days | 221 days |
| 28°F | 206 days | 227 days | 249 days |
| 24°F | 229 days | 251 days | 275 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 |
|---|---|---|---|
| 19605 | 7a | 0 to 5°F | 3 km |
| 19510 | 7a | 0 to 5°F | 5 km |
| 19560 | 7a | 0 to 5°F | 5 km |
| 19533 | 7a | 0 to 5°F | 5 km |
| 19522 | 7a | 0 to 5°F | 10 km |
| 19547 | 7a | 0 to 5°F | 14 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 USC00367322, at 40.4269, -75.9319, elevation 110 m (360 ft).
- Data quality: Representative (10+ years), 15 years of freeze data.
- Average days per year at or below 32°F: 106.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Reading Spaatz Field (7 km)
- Blue Marsh Lake (10 km)
- Hamburg (15 km)
- Rodale Rsch Center (22 km)
- Hopewell Morgantown (30 km)
- Pottstown Limerick Airport (38 km)
- Glenmoore (40 km)
- New Holland 2 SE (41 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.