Frost dates for Lewistown, PA
At Lewistown, the median last spring frost (32°F) is Apr 21 and the median first fall frost is Oct 24, for a typical growing season of 185 days. For a 90% chance that the last frost has passed, wait until May 9. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 21Last spring frost (median)50% chance of 32°F after this date
- May 9Safer planting date10% chance of 32°F after this date
- Oct 24First fall frost (median)50% chance of 32°F by this date
- 185 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 18 | May 2 | May 19 |
| 32°F | Apr 6 | Apr 21 | May 9 |
| 28°F | Mar 24 | Apr 6 | Apr 21 |
| 24°F | Mar 9 | Mar 26 | Apr 8 |
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 29 | Oct 13 | Oct 27 |
| 32°F | Oct 7 | Oct 24 | Nov 7 |
| 28°F | Oct 21 | Nov 5 | Nov 19 |
| 24°F | Nov 4 | Nov 18 | 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 | 137 days | 161 days | 181 days |
| 32°F | 162 days | 185 days | 206 days |
| 28°F | 190 days | 211 days | 231 days |
| 24°F | 219 days | 238 days | 259 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 |
|---|---|---|---|
| 17044 | 7a | 0 to 5°F | 2 km |
| 17029 | 7a | 0 to 5°F | 5 km |
| 17009 | 7a | 0 to 5°F | 6 km |
| 17099 | 7a | 0 to 5°F | 6 km |
| 17058 | 7a | 0 to 5°F | 10 km |
| 17084 | 6b | -5 to 0°F | 11 km |
| 17004 | 6b | -5 to 0°F | 14 km |
| 17082 | 7a | 0 to 5°F | 14 km |
| 17059 | 7a | 0 to 5°F | 15 km |
| 17054 | 7a | 0 to 5°F | 17 km |
| 17056 | 7a | 0 to 5°F | 19 km |
| 17035 | 7a | 0 to 5°F | 20 km |
| 17051 | 7a | 0 to 5°F | 22 km |
| 17049 | 6b | -5 to 0°F | 27 km |
| 17094 | 6b | -5 to 0°F | 29 km |
| 17062 | 6b | -5 to 0°F | 33 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 USC00364992, at 40.5864, -77.5692, elevation 140 m (460 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 122.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- State College (34 km)
- Millheim (34 km)
- Bloserville 1 N (40 km)
- Laurelton Center (46 km)
- Raystown Lake 2 (48 km)
- Raystown HQ (48 km)
- Carlisle Water Plant (51 km)
- Shippensburg (59 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.