Frost dates for Charleroi Lock 4, PA
At Charleroi Lock 4, the median last spring frost (32°F) is Apr 13 and the median first fall frost is Nov 5, for a typical growing season of 205 days. For a 90% chance that the last frost has passed, wait until May 5. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 13Last spring frost (median)50% chance of 32°F after this date
- May 5Safer planting date10% chance of 32°F after this date
- Nov 5First 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 11 | Apr 27 | May 16 |
| 32°F | Mar 29 | Apr 13 | May 5 |
| 28°F | Mar 15 | Mar 31 | Apr 14 |
| 24°F | Mar 3 | Mar 20 | Apr 2 |
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 10 | Oct 25 | Nov 5 |
| 32°F | Oct 25 | Nov 5 | Nov 18 |
| 28°F | Nov 3 | Nov 16 | Dec 3 |
| 24°F | Nov 9 | Nov 27 | 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 | 158 days | 180 days | 203 days |
| 32°F | 182 days | 205 days | 227 days |
| 28°F | 209 days | 230 days | 253 days |
| 24°F | 229 days | 251 days | 277 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 |
|---|---|---|---|
| 15062 | 6b | -5 to 0°F | 1 km |
| 15022 | 6b | -5 to 0°F | 4 km |
| 15432 | 6b | -5 to 0°F | 5 km |
| 15063 | 6b | -5 to 0°F | 5 km |
| 15412 | 6b | -5 to 0°F | 6 km |
| 15423 | 6b | -5 to 0°F | 6 km |
| 15434 | 6b | -5 to 0°F | 7 km |
| 15466 | 6b | -5 to 0°F | 8 km |
| 15483 | 6b | -5 to 0°F | 8 km |
| 15067 | 6b | -5 to 0°F | 9 km |
| 15438 | 6b | -5 to 0°F | 9 km |
| 15419 | 6b | -5 to 0°F | 10 km |
| 15314 | 6b | -5 to 0°F | 10 km |
| 15427 | 6b | -5 to 0°F | 11 km |
| 15331 | 6b | -5 to 0°F | 12 km |
| 15332 | 6b | -5 to 0°F | 13 km |
| 15358 | 6b | -5 to 0°F | 14 km |
| 15313 | 6b | -5 to 0°F | 14 km |
| 15444 | 6b | -5 to 0°F | 15 km |
| 15442 | 6b | -5 to 0°F | 15 km |
| 15417 | 6b | -5 to 0°F | 16 km |
| 15429 | 6b | -5 to 0°F | 16 km |
| 15333 | 6b | -5 to 0°F | 16 km |
| 15368 | 6b | -5 to 0°F | 17 km |
| 15450 | 6b | -5 to 0°F | 17 km |
| 15433 | 6b | -5 to 0°F | 19 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 USC00361377, at 40.1467, -79.8986, elevation 228 m (749 ft).
- Data quality: Estimated from nearby stations (2+ years), 10 years of freeze data.
- Average days per year at or below 32°F: 108.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Donora 1 SW (3 km)
- McKeesport (22 km)
- Pittsburgh Allegheny Co Airport (23 km)
- Washington 3 NE (25 km)
- Braddock Lock 2 (27 km)
- Uniontown 1 NE (30 km)
- Connellsville 2 SSW (31 km)
- Murrysville 2 SW (33 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.