Frost dates for Hamburg, PA
At Hamburg, the median last spring frost (32°F) is Apr 16 and the median first fall frost is Oct 25, for a typical growing season of 189 days. For a 90% chance that the last frost has passed, wait until May 3. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 16Last spring frost (median)50% chance of 32°F after this date
- May 3Safer planting date10% chance of 32°F after this date
- Oct 25First fall frost (median)50% chance of 32°F by this date
- 189 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 16 | Apr 30 | May 16 |
| 32°F | Apr 2 | Apr 16 | May 3 |
| 28°F | Mar 20 | Apr 3 | Apr 17 |
| 24°F | Mar 8 | Mar 25 | Apr 5 |
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 1 | Oct 13 | Oct 30 |
| 32°F | Oct 9 | Oct 25 | Nov 7 |
| 28°F | Oct 18 | Nov 3 | Nov 17 |
| 24°F | Nov 1 | Nov 15 | Dec 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 | 144 days | 165 days | 185 days |
| 32°F | 167 days | 189 days | 209 days |
| 28°F | 194 days | 214 days | 233 days |
| 24°F | 216 days | 235 days | 258 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 |
|---|---|---|---|
| 19526 | 7a | 0 to 5°F | 1 km |
| 19549 | 7a | 0 to 5°F | 5 km |
| 19555 | 7a | 0 to 5°F | 7 km |
| 19516 | 7a | 0 to 5°F | 7 km |
| 19541 | 7a | 0 to 5°F | 8 km |
| 19534 | 6b | -5 to 0°F | 10 km |
| 19554 | 7a | 0 to 5°F | 10 km |
| 17922 | 7a | 0 to 5°F | 11 km |
| 19564 | 7a | 0 to 5°F | 11 km |
| 17961 | 7a | 0 to 5°F | 12 km |
| 19529 | 6b | -5 to 0°F | 15 km |
| 17960 | 6b | -5 to 0°F | 17 km |
| 19559 | 7a | 0 to 5°F | 18 km |
| 17979 | 7a | 0 to 5°F | 18 km |
| 17929 | 7a | 0 to 5°F | 19 km |
| 17972 | 7a | 0 to 5°F | 20 km |
| 17933 | 7a | 0 to 5°F | 22 km |
| 19507 | 7a | 0 to 5°F | 24 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 USC00363632, at 40.5517, -75.9911, elevation 112 m (369 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 121.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Reading 4 NNW (15 km)
- Blue Marsh Lake (19 km)
- Reading Spaatz Field (21 km)
- Rodale Rsch Center (23 km)
- Mahanoy City 2 N (34 km)
- Lehighton 1ssw (39 km)
- Hopewell Morgantown (45 km)
- Lebanon 2 W (47 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.