Frost dates for Donora 1 SW, PA
At Donora 1 SW, the median last spring frost (32°F) is Apr 27 and the median first fall frost is Oct 22, for a typical growing season of 177 days. For a 90% chance that the last frost has passed, wait until May 15. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 27Last spring frost (median)50% chance of 32°F after this date
- May 15Safer planting date10% chance of 32°F after this date
- Oct 22First fall frost (median)50% chance of 32°F by this date
- 177 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 22 | May 6 | May 22 |
| 32°F | Apr 11 | Apr 27 | May 15 |
| 28°F | Mar 31 | Apr 14 | May 4 |
| 24°F | Mar 16 | Apr 1 | Apr 17 |
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 30 | Oct 12 | Oct 25 |
| 32°F | Oct 8 | Oct 22 | Nov 4 |
| 28°F | Oct 19 | Nov 1 | Nov 15 |
| 24°F | Oct 31 | Nov 13 | 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 | 137 days | 156 days | 176 days |
| 32°F | 156 days | 177 days | 198 days |
| 28°F | 175 days | 201 days | 221 days |
| 24°F | 202 days | 224 days | 248 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 |
|---|---|---|---|
| 15033 | 6b | -5 to 0°F | 2 km |
| 15072 | 6b | -5 to 0°F | 3 km |
| 15087 | 6b | -5 to 0°F | 4 km |
| 15012 | 6b | -5 to 0°F | 5 km |
| 15020 | 6b | -5 to 0°F | 10 km |
| 15492 | 6b | -5 to 0°F | 10 km |
| 15038 | 6b | -5 to 0°F | 11 km |
| 15448 | 6b | -5 to 0°F | 12 km |
| 15089 | 6b | -5 to 0°F | 12 km |
| 15473 | 6b | -5 to 0°F | 13 km |
| 15640 | 6b | -5 to 0°F | 13 km |
| 15479 | 6b | -5 to 0°F | 14 km |
| 15482 | 6b | -5 to 0°F | 14 km |
| 15695 | 6b | -5 to 0°F | 15 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 USC00362190, at 40.1636, -79.8694, elevation 232 m (762 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 116.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Charleroi Lock 4 (3 km)
- McKeesport (20 km)
- Pittsburgh Allegheny Co Airport (22 km)
- Braddock Lock 2 (25 km)
- Washington 3 NE (27 km)
- Connellsville 2 SSW (30 km)
- Murrysville 2 SW (30 km)
- Uniontown 1 NE (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.