Millville, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.8 °C (low) to 12.9 °C (high). Annual precipitation averages 898.2 Millimeters. Millville is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.4 °C | -4.4 °C | 24.64 mm |
| February | -12.6 °C | -1.9 °C | 26.67 mm |
| March | -5.4 °C | 5.1 °C | 48.51 mm |
| April | 1.4 °C | 13.3 °C | 85.34 mm |
| May | 8.2 °C | 20.4 °C | 114.81 mm |
| June | 13.9 °C | 25.8 °C | 135.89 mm |
| July | 16.2 °C | 27.9 °C | 107.7 mm |
| August | 14.8 °C | 26.7 °C | 117.86 mm |
| September | 10.3 °C | 22.8 °C | 97.54 mm |
| October | 3.3 °C | 15.1 °C | 62.74 mm |
| November | -3.5 °C | 5.9 °C | 44.7 mm |
| December | -10.2 °C | -1.4 °C | 31.75 mm |
| Annual | 1.8 °C | 12.9 °C | 898.15 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |