Greenfield, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.9 °C (low) to 12.2 °C (high). Annual precipitation averages 798.8 Millimeters. Greenfield is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.9 °C | -5.4 °C | 19.56 mm |
| February | -13.2 °C | -2.8 °C | 22.35 mm |
| March | -6.2 °C | 4.2 °C | 37.59 mm |
| April | 1.3 °C | 12.5 °C | 71.88 mm |
| May | 8.6 °C | 19.8 °C | 107.7 mm |
| June | 14.5 °C | 25.1 °C | 119.63 mm |
| July | 16.8 °C | 27.7 °C | 99.31 mm |
| August | 15.5 °C | 26.3 °C | 104.65 mm |
| September | 10.8 °C | 22.2 °C | 85.34 mm |
| October | 3.6 °C | 14.1 °C | 64.01 mm |
| November | -3.6 °C | 5.2 °C | 36.83 mm |
| December | -10.9 °C | -2.6 °C | 29.97 mm |
| Annual | 1.9 °C | 12.2 °C | 798.82 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |