Farrell, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.8 °F (low) to 61.2 °F (high). Annual precipitation averages 41.2 Inches. Farrell is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.8 °F | 35.4 °F | 2.84 in. |
| February | 19.5 °F | 38.4 °F | 2.27 in. |
| March | 27.1 °F | 47.7 °F | 2.88 in. |
| April | 37.3 °F | 61.5 °F | 3.74 in. |
| May | 47.5 °F | 72.1 °F | 3.84 in. |
| June | 56.4 °F | 80.4 °F | 4.43 in. |
| July | 60.5 °F | 84.1 °F | 4.45 in. |
| August | 58.8 °F | 82.7 °F | 3.59 in. |
| September | 52.1 °F | 76.3 °F | 3.97 in. |
| October | 41.3 °F | 64.0 °F | 3.15 in. |
| November | 32.7 °F | 51.0 °F | 2.95 in. |
| December | 25.0 °F | 40.2 °F | 3.13 in. |
| Annual | 39.8 °F | 61.2 °F | 41.24 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |