Youngsville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3 °C (low) to 14.5 °C (high). Annual precipitation averages 1170.4 Millimeters. Youngsville is located in USDA Plant Hardiness Zone 6a. 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 | -8.6 °C | 0.3 °C | 86.11 mm |
| February | -8.6 °C | 1.7 °C | 63.25 mm |
| March | -4.7 °C | 6.7 °C | 80.52 mm |
| April | 1.1 °C | 14.4 °C | 99.82 mm |
| May | 7.1 °C | 21 °C | 102.36 mm |
| June | 12.1 °C | 25.2 °C | 116.33 mm |
| July | 14.3 °C | 27.5 °C | 122.94 mm |
| August | 13.6 °C | 26.8 °C | 102.36 mm |
| September | 10.1 °C | 23.1 °C | 102.36 mm |
| October | 4.3 °C | 16.1 °C | 105.66 mm |
| November | -0.5 °C | 8.8 °C | 93.22 mm |
| December | -4.7 °C | 2.8 °C | 95.5 mm |
| Annual | 3 °C | 14.5 °C | 1170.43 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 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 |