Mount Jewett, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.8 °C (low) to 12.2 °C (high). Annual precipitation averages 1272.8 Millimeters. Mount Jewett 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 | -9.9 °C | -1.6 °C | 101.35 mm |
| February | -9.7 °C | -0.2 °C | 72.64 mm |
| March | -5.5 °C | 4.7 °C | 93.98 mm |
| April | 0.7 °C | 12.3 °C | 111.76 mm |
| May | 6.4 °C | 18.7 °C | 111.25 mm |
| June | 10.8 °C | 22.7 °C | 120.4 mm |
| July | 13 °C | 24.7 °C | 122.43 mm |
| August | 12.2 °C | 23.8 °C | 116.84 mm |
| September | 8.8 °C | 20.2 °C | 105.92 mm |
| October | 3.1 °C | 13.6 °C | 109.47 mm |
| November | -1.6 °C | 6.8 °C | 103.63 mm |
| December | -6.3 °C | 1.1 °C | 103.12 mm |
| Annual | 1.8 °C | 12.2 °C | 1272.79 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |