Frost dates for Harrisburg 1 NE, PA
At Harrisburg 1 NE, the median last spring frost (32°F) is Apr 15 and the median first fall frost is Oct 23, for a typical growing season of 189 days. For a 90% chance that the last frost has passed, wait until May 2. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 15Last spring frost (median)50% chance of 32°F after this date
- May 2Safer planting date10% chance of 32°F after this date
- Oct 23First 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 14 | Apr 30 | May 15 |
| 32°F | Apr 1 | Apr 15 | May 2 |
| 28°F | Mar 19 | Apr 3 | Apr 16 |
| 24°F | Mar 6 | Mar 22 | 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 | Sep 28 | Oct 12 | Oct 28 |
| 32°F | Oct 7 | Oct 23 | Nov 7 |
| 28°F | Oct 20 | Nov 5 | Nov 21 |
| 24°F | Nov 1 | Nov 17 | Dec 4 |
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 | 143 days | 165 days | 184 days |
| 32°F | 167 days | 189 days | 210 days |
| 28°F | 193 days | 214 days | 236 days |
| 24°F | 218 days | 239 days | 261 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 |
|---|---|---|---|
| 17103 | 7a | 0 to 5°F | 1 km |
| 17120 | 7a | 0 to 5°F | 2 km |
| 17104 | 7a | 0 to 5°F | 3 km |
| 17102 | 7a | 0 to 5°F | 3 km |
| 17101 | 7a | 0 to 5°F | 3 km |
| 17109 | 7a | 0 to 5°F | 4 km |
| 17043 | 7a | 0 to 5°F | 5 km |
| 17110 | 7a | 0 to 5°F | 5 km |
| 17093 | 7a | 0 to 5°F | 6 km |
| 17111 | 7a | 0 to 5°F | 8 km |
| 17025 | 7a | 0 to 5°F | 9 km |
| 17053 | 7a | 0 to 5°F | 14 km |
| 17020 | 7a | 0 to 5°F | 21 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 USC00363698, at 40.2817, -76.8706, elevation 128 m (420 ft).
- Data quality: Representative (10+ years), 22 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
- Harrisburg Cptl Cy Airport (7 km)
- Middletown Harrisburg Intl Airport (13 km)
- Dehart Dam (22 km)
- Carlisle Water Plant (28 km)
- Lebanon 2 W (35 km)
- York Airport (40 km)
- Landisville 2 NW (42 km)
- York 3 SSW Pump Station (42 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.