| 2023 Hardiness Zone: | 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 1b: -15F to -10F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| 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: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 15642 - Irwin, PA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 19 | 20 | 28 | 37 | 47 | 56 | 61 | 60 | 53 | 41 | 33 | 24 | 40 |
| Avg Max Temp (°F) | 36 | 40 | 50 | 61 | 71 | 80 | 83 | 82 | 75 | 64 | 52 | 41 | 61 |
| Avg Precip (In.) | 2.73 | 2.42 | 3.33 | 3.32 | 4.02 | 3.97 | 4.15 | 3.81 | 3.55 | 2.52 | 3.29 | 2.87 | 40 |