Slippery Rock, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.6 °C (low) to 15.6 °C (high). Annual precipitation averages 1109.5 Millimeters. Slippery Rock 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 | -8.1 °C | 1.7 °C | 77.98 mm |
| February | -7.4 °C | 3.5 °C | 65.02 mm |
| March | -3.4 °C | 8.4 °C | 83.06 mm |
| April | 2.3 °C | 15.6 °C | 99.31 mm |
| May | 7.9 °C | 21.3 °C | 100.58 mm |
| June | 12.9 °C | 25.8 °C | 120.9 mm |
| July | 15.1 °C | 28.1 °C | 116.84 mm |
| August | 14.2 °C | 27.4 °C | 96.52 mm |
| September | 10.4 °C | 23.9 °C | 99.06 mm |
| October | 4.5 °C | 17.1 °C | 85.6 mm |
| November | -0.4 °C | 10.2 °C | 84.84 mm |
| December | -4.6 °C | 4.2 °C | 79.76 mm |
| Annual | 3.6 °C | 15.6 °C | 1109.47 mm |
| 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 : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |