Warren, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.1 °C (low) to 14.7 °C (high). Annual precipitation averages 1189.7 Millimeters. Warren 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 | -8.5 °C | 0.3 °C | 90.17 mm |
| February | -8.4 °C | 1.8 °C | 68.33 mm |
| March | -4.6 °C | 6.8 °C | 82.55 mm |
| April | 1.3 °C | 14.7 °C | 104.9 mm |
| May | 7.2 °C | 21.2 °C | 106.68 mm |
| June | 12.3 °C | 25.3 °C | 117.09 mm |
| July | 14.5 °C | 27.8 °C | 123.7 mm |
| August | 13.8 °C | 27.1 °C | 103.89 mm |
| September | 10.3 °C | 23.4 °C | 101.09 mm |
| October | 4.4 °C | 16.3 °C | 102.11 mm |
| November | -0.4 °C | 9 °C | 92.71 mm |
| December | -4.7 °C | 2.9 °C | 96.52 mm |
| Annual | 3.1 °C | 14.7 °C | 1189.74 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |