Butler, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.5 °C (low) to 16.3 °C (high). Annual precipitation averages 1088.9 Millimeters. Butler is located in USDA Plant Hardiness Zone 6b. 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 | -6.8 °C | 2.3 °C | 84.07 mm |
| February | -6.3 °C | 4.1 °C | 64.52 mm |
| March | -2.5 °C | 9.2 °C | 82.3 mm |
| April | 2.9 °C | 16.7 °C | 96.27 mm |
| May | 8.8 °C | 22.3 °C | 97.79 mm |
| June | 13.8 °C | 26.7 °C | 109.73 mm |
| July | 16.1 °C | 28.7 °C | 106.68 mm |
| August | 15.2 °C | 28.1 °C | 99.31 mm |
| September | 11.4 °C | 24.5 °C | 98.81 mm |
| October | 5.3 °C | 17.6 °C | 82.8 mm |
| November | 0.2 °C | 10.8 °C | 84.58 mm |
| December | -3.8 °C | 4.8 °C | 82.04 mm |
| Annual | 4.5 °C | 16.3 °C | 1088.9 mm |
| 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |