Frost dates for Octoraro Lake, PA
At Octoraro Lake, the median last spring frost (32°F) is Apr 26 and the median first fall frost is Oct 22, for a typical growing season of 179 days. For a 90% chance that the last frost has passed, wait until May 10. Nearby ZIP codes are in USDA hardiness zone 7a.
- Apr 26Last spring frost (median)50% chance of 32°F after this date
- May 10Safer planting date10% chance of 32°F after this date
- Oct 22First fall frost (median)50% chance of 32°F by this date
- 179 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 21 | May 4 | May 19 |
| 32°F | Apr 9 | Apr 26 | May 10 |
| 28°F | Mar 26 | Apr 11 | Apr 30 |
| 24°F | Mar 11 | Mar 28 | Apr 15 |
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 25 |
| 32°F | Oct 9 | Oct 22 | Nov 3 |
| 28°F | Oct 17 | Oct 31 | Nov 13 |
| 24°F | Oct 26 | Nov 10 | Nov 30 |
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 | 140 days | 159 days | 178 days |
| 32°F | 159 days | 179 days | 198 days |
| 28°F | 182 days | 202 days | 223 days |
| 24°F | 204 days | 228 days | 253 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 |
|---|---|---|---|
| 19362 | 7a | 0 to 5°F | 5 km |
| 17536 | 7a | 0 to 5°F | 6 km |
| 19363 | 7a | 0 to 5°F | 7 km |
| 21911 | 7a | 0 to 5°F | 11 km |
| 17566 | 7a | 0 to 5°F | 12 km |
| 17509 | 7a | 0 to 5°F | 12 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 USC00366508, at 39.7956, -76.0442, elevation 79 m (260 ft).
- Data quality: Standard (24+ years of data), 25 years of freeze data.
- Average days per year at or below 32°F: 125.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Avondale 2 N (23 km)
- Coatesville 2 W (26 km)
- New Holland 2 SE (31 km)
- Safe Harbor Dam (33 km)
- Lancaster 2ne Fltr Plant (34 km)
- W Chester 2 NW (40 km)
- Glenmoore (42 km)
- Lancaster Airport (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.