Frost dates for Harrisburg Cptl Cy Airport, PA
At Harrisburg Cptl Cy Airport, the median last spring frost (32°F) is Apr 9 and the median first fall frost is Nov 1, for a typical growing season of 205 days. For a 90% chance that the last frost has passed, wait until Apr 25. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 9Last spring frost (median)50% chance of 32°F after this date
- Apr 25Safer planting date10% chance of 32°F after this date
- Nov 1First fall frost (median)50% chance of 32°F by this date
- 205 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 22 | May 10 |
| 32°F | Mar 27 | Apr 9 | Apr 25 |
| 28°F | Mar 13 | Mar 29 | Apr 9 |
| 24°F | Feb 27 | Mar 15 | Mar 30 |
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 7 | Oct 20 | Nov 3 |
| 32°F | Oct 16 | Nov 1 | Nov 15 |
| 28°F | Oct 28 | Nov 12 | Dec 1 |
| 24°F | Nov 10 | Nov 28 | Dec 16 |
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 | 161 days | 180 days | 201 days |
| 32°F | 182 days | 205 days | 225 days |
| 28°F | 209 days | 231 days | 253 days |
| 24°F | 235 days | 257 days | 279 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 |
|---|---|---|---|
| 17070 | 7a | 0 to 5°F | 2 km |
| 17113 | 7a | 0 to 5°F | 3 km |
| 17011 | 7a | 0 to 5°F | 7 km |
| 17339 | 7a | 0 to 5°F | 9 km |
| 17027 | 7a | 0 to 5°F | 13 km |
| 17055 | 7a | 0 to 5°F | 13 km |
| 17019 | 7a | 0 to 5°F | 20 km |
| 17323 | 7a | 0 to 5°F | 22 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 USW00014751, at 40.2172, -76.8514, elevation 104 m (340 ft).
- Data quality: Representative (10+ years), 18 years of freeze data.
- Average days per year at or below 32°F: 102.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Harrisburg 1 NE (7 km)
- Middletown Harrisburg Intl Airport (8 km)
- Dehart Dam (28 km)
- Carlisle Water Plant (29 km)
- York Airport (33 km)
- York 3 SSW Pump Station (35 km)
- Lebanon 2 W (35 km)
- Landisville 2 NW (38 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.