Merrifield, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.2 °F (low) to 51.5 °F (high). Annual precipitation averages 28.8 Inches. Merrifield is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.1 °F | 19.0 °F | 0.75 in. |
| February | 2.7 °F | 24.6 °F | 0.78 in. |
| March | 16.2 °F | 37.6 °F | 1.39 in. |
| April | 30.5 °F | 52.0 °F | 2.27 in. |
| May | 43.8 °F | 65.4 °F | 3.51 in. |
| June | 54.3 °F | 75.0 °F | 4.35 in. |
| July | 58.5 °F | 79.8 °F | 4.4 in. |
| August | 55.6 °F | 77.7 °F | 3.44 in. |
| September | 47.2 °F | 69.1 °F | 2.85 in. |
| October | 34.9 °F | 54.4 °F | 2.82 in. |
| November | 22.0 °F | 38.2 °F | 1.32 in. |
| December | 9.0 °F | 24.7 °F | 0.93 in. |
| Annual | 31.2 °F | 51.5 °F | 28.81 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |