Millville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.6 °C (low) to 16.2 °C (high). Annual precipitation averages 1148.6 Millimeters. Millville is located in USDA Plant Hardiness Zone 6b. 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 | -7.2 °C | 2.1 °C | 90.17 mm |
| February | -6.4 °C | 3.7 °C | 62.99 mm |
| March | -2.4 °C | 8.7 °C | 91.44 mm |
| April | 3.3 °C | 16.2 °C | 95.76 mm |
| May | 8.9 °C | 22.2 °C | 95 mm |
| June | 14.1 °C | 26.7 °C | 119.89 mm |
| July | 16.4 °C | 29.3 °C | 111.51 mm |
| August | 15.6 °C | 28.3 °C | 99.31 mm |
| September | 11.5 °C | 24.4 °C | 112.52 mm |
| October | 5.3 °C | 17.6 °C | 102.62 mm |
| November | 0.2 °C | 10.8 °C | 78.74 mm |
| December | -3.9 °C | 4.7 °C | 88.65 mm |
| Annual | 4.6 °C | 16.2 °C | 1148.6 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 6b : -20.6°C to -17.8°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 |