Frost dates for Pittsburgh Allegheny Co Airport, PA
At Pittsburgh Allegheny Co Airport, the median last spring frost (32°F) is Apr 18 and the median first fall frost is Oct 28, for a typical growing season of 193 days. For a 90% chance that the last frost has passed, wait until May 6. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- Apr 18Last spring frost (median)50% chance of 32°F after this date
- May 6Safer planting date10% chance of 32°F after this date
- Oct 28First fall frost (median)50% chance of 32°F by this date
- 193 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 16 | Apr 29 | May 17 |
| 32°F | Apr 2 | Apr 18 | May 6 |
| 28°F | Mar 23 | Apr 5 | Apr 21 |
| 24°F | Mar 12 | Mar 28 | 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 | Oct 4 | Oct 17 | Oct 29 |
| 32°F | Oct 14 | Oct 28 | Nov 10 |
| 28°F | Oct 28 | Nov 8 | Nov 22 |
| 24°F | Nov 5 | Nov 18 | Dec 5 |
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 | 150 days | 169 days | 188 days |
| 32°F | 171 days | 193 days | 212 days |
| 28°F | 196 days | 216 days | 238 days |
| 24°F | 217 days | 237 days | 262 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 |
|---|---|---|---|
| 15123 | 6b | -5 to 0°F | 1 km |
| 15122 | 6b | -5 to 0°F | 2 km |
| 15034 | 6b | -5 to 0°F | 3 km |
| 15236 | 6b | -5 to 0°F | 5 km |
| 15227 | 6b | -5 to 0°F | 5 km |
| 15207 | 6b | -5 to 0°F | 5 km |
| 15025 | 6b | -5 to 0°F | 6 km |
| 15210 | 6b | -5 to 0°F | 8 km |
| 15234 | 6b | -5 to 0°F | 8 km |
| 15226 | 6b | -5 to 0°F | 9 km |
| 15203 | 7a | 0 to 5°F | 9 km |
| 15129 | 6b | -5 to 0°F | 9 km |
| 15213 | 6b | -5 to 0°F | 10 km |
| 15102 | 6b | -5 to 0°F | 10 km |
| 15228 | 6b | -5 to 0°F | 11 km |
| 15282 | 6b | -5 to 0°F | 11 km |
| 15216 | 6b | -5 to 0°F | 11 km |
| 15219 | 6b | -5 to 0°F | 11 km |
| 15243 | 6b | -5 to 0°F | 13 km |
| 15241 | 6b | -5 to 0°F | 14 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 USW00014762, at 40.3547, -79.9217, elevation 380 m (1,248 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 106.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- McKeesport (5 km)
- Braddock Lock 2 (7 km)
- Murrysville 2 SW (18 km)
- Donora 1 SW (22 km)
- Emsworth L/d Ohio River (22 km)
- Acmetonia Lock 3 (22 km)
- Charleroi Lock 4 (23 km)
- Pittsburgh Intl Airport (29 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.