| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 70b - Monongahela Transition Zone |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 15301 - Washington, PA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 20 | 21 | 29 | 37 | 48 | 57 | 61 | 60 | 53 | 41 | 33 | 25 | 40 |
| Avg Max Temp (°F) | 37 | 40 | 51 | 62 | 72 | 80 | 83 | 82 | 76 | 65 | 52 | 41 | 62 |
| Avg Precip (In.) | 2.78 | 2.45 | 3.28 | 3.26 | 4.03 | 4.02 | 4.17 | 3.61 | 3.31 | 2.46 | 3.11 | 2.87 | 39.34 |