Knoxville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.3 °F (low) to 57.9 °F (high). Annual precipitation averages 37.1 Inches. Knoxville is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.9 °F | 32.3 °F | 2.29 in. |
| February | 14.9 °F | 35.1 °F | 1.81 in. |
| March | 21.7 °F | 43.4 °F | 2.63 in. |
| April | 32.2 °F | 57.1 °F | 3.05 in. |
| May | 42.9 °F | 69.3 °F | 3.4 in. |
| June | 52.1 °F | 77.5 °F | 3.91 in. |
| July | 56.2 °F | 81.5 °F | 3.74 in. |
| August | 54.9 °F | 80.2 °F | 3.6 in. |
| September | 48.0 °F | 73.2 °F | 3.82 in. |
| October | 37.6 °F | 60.8 °F | 3.61 in. |
| November | 28.5 °F | 47.5 °F | 2.75 in. |
| December | 20.8 °F | 37.0 °F | 2.5 in. |
| Annual | 35.3 °F | 57.9 °F | 37.11 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |