Montello, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.3 °F (low) to 56.1 °F (high). Annual precipitation averages 35.7 Inches. Montello is located in USDA Plant Hardiness Zone 5a. 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 | 8.5 °F | 26.5 °F | 1.36 in. |
| February | 11.2 °F | 30.8 °F | 1.26 in. |
| March | 21.9 °F | 42.6 °F | 1.88 in. |
| April | 33.6 °F | 56.2 °F | 3.66 in. |
| May | 46.0 °F | 68.7 °F | 4.32 in. |
| June | 56.0 °F | 78.1 °F | 5.09 in. |
| July | 59.9 °F | 82.0 °F | 4.25 in. |
| August | 57.8 °F | 80.1 °F | 3.93 in. |
| September | 49.3 °F | 72.7 °F | 3.46 in. |
| October | 37.7 °F | 59.5 °F | 2.83 in. |
| November | 26.4 °F | 44.5 °F | 2.03 in. |
| December | 15.5 °F | 31.7 °F | 1.67 in. |
| Annual | 35.3 °F | 56.1 °F | 35.74 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |