| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Sep. 21 - Sep. 30 |
| Average Last Frost Date: | Jun. 1 - Jun. 10 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 62d - Unglaciated Allegheney High Plateau |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 15857 - Saint Marys, PA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 14 | 23 | 32 | 42 | 51 | 55 | 54 | 47 | 36 | 29 | 20 | 35 |
| Avg Max Temp (°F) | 31 | 34 | 44 | 57 | 68 | 76 | 79 | 78 | 71 | 60 | 46 | 35 | 56 |
| Avg Precip (In.) | 3.16 | 2.59 | 3.5 | 3.63 | 4.1 | 5.25 | 4.5 | 4.24 | 4.22 | 3.38 | 3.81 | 3.46 | 45.85 |