Zimmerman, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.6 °F (low) to 53.8 °F (high). Annual precipitation averages 31.4 Inches. Zimmerman 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.7 °F | 21.8 °F | 0.77 in. |
| February | 7.0 °F | 26.7 °F | 0.85 in. |
| March | 19.5 °F | 39.5 °F | 1.58 in. |
| April | 32.7 °F | 54.7 °F | 2.77 in. |
| May | 45.5 °F | 67.8 °F | 4.18 in. |
| June | 55.8 °F | 77.3 °F | 4.32 in. |
| July | 60.4 °F | 81.7 °F | 4.24 in. |
| August | 57.5 °F | 79.4 °F | 4.06 in. |
| September | 49.2 °F | 71.9 °F | 3.16 in. |
| October | 36.6 °F | 57.1 °F | 2.76 in. |
| November | 24.0 °F | 40.8 °F | 1.58 in. |
| December | 11.2 °F | 27.0 °F | 1.1 in. |
| Annual | 33.6 °F | 53.8 °F | 31.37 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |