Frost dates for Natrona Lock 4, PA
At Natrona Lock 4, the median last spring frost (32°F) is Apr 16 and the median first fall frost is Nov 2, for a typical growing season of 199 days. For a 90% chance that the last frost has passed, wait until May 2. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 16Last spring frost (median)50% chance of 32°F after this date
- May 2Safer planting date10% chance of 32°F after this date
- Nov 2First fall frost (median)50% chance of 32°F by this date
- 199 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 29 | May 16 |
| 32°F | Mar 31 | Apr 16 | May 2 |
| 28°F | Mar 19 | Apr 3 | Apr 16 |
| 24°F | Mar 10 | Mar 25 | Apr 6 |
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 21 | Nov 3 |
| 32°F | Oct 20 | Nov 2 | Nov 16 |
| 28°F | Nov 2 | Nov 14 | Dec 1 |
| 24°F | Nov 9 | Nov 25 | Dec 12 |
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 | 153 days | 174 days | 194 days |
| 32°F | 178 days | 199 days | 218 days |
| 28°F | 206 days | 224 days | 245 days |
| 24°F | 224 days | 245 days | 268 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 |
|---|---|---|---|
| 15014 | 6b | -5 to 0°F | 2 km |
| 15065 | 6b | -5 to 0°F | 3 km |
| 15030 | 6b | -5 to 0°F | 6 km |
| 15068 | 6b | -5 to 0°F | 6 km |
| 15084 | 6b | -5 to 0°F | 7 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 USC00366151, at 40.6142, -79.7192, elevation 232 m (760 ft).
- Data quality: Estimated from nearby stations (2+ years), 9 years of freeze data.
- Average days per year at or below 32°F: 117.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Schenley Lock 5 (9 km)
- Acmetonia Lock 3 (12 km)
- Salina 3 W (19 km)
- Ford City 4 S Dam (21 km)
- Murrysville 2 SW (22 km)
- Braddock Lock 2 (27 km)
- Loyalhanna Lake (29 km)
- Butler 2 SW (30 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.