West Decatur, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.5 °F (low) to 58.3 °F (high). Annual precipitation averages 43.2 Inches. West Decatur is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.8 °F | 33.3 °F | 3.07 in. |
| February | 17.6 °F | 36.3 °F | 2.53 in. |
| March | 24.5 °F | 45.2 °F | 3.43 in. |
| April | 35.2 °F | 58.9 °F | 3.82 in. |
| May | 45.6 °F | 69.5 °F | 3.97 in. |
| June | 54.2 °F | 77.0 °F | 4.44 in. |
| July | 58.4 °F | 81.0 °F | 4.05 in. |
| August | 56.8 °F | 79.5 °F | 3.89 in. |
| September | 49.6 °F | 72.6 °F | 4.06 in. |
| October | 38.8 °F | 60.5 °F | 3.69 in. |
| November | 29.7 °F | 48.6 °F | 3.0 in. |
| December | 22.7 °F | 37.6 °F | 3.27 in. |
| Annual | 37.5 °F | 58.3 °F | 43.22 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |