Mount Sterling, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.7 °C (low) to 12.8 °C (high). Annual precipitation averages 954.5 Millimeters. Mount Sterling is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.7 °C | -3.9 °C | 32.77 mm |
| February | -10.8 °C | -1.3 °C | 29.97 mm |
| March | -4.5 °C | 5.6 °C | 50.8 mm |
| April | 2.1 °C | 13.3 °C | 100.84 mm |
| May | 8.6 °C | 19.8 °C | 114.3 mm |
| June | 14.3 °C | 24.9 °C | 146.05 mm |
| July | 16.6 °C | 27.1 °C | 116.08 mm |
| August | 15.4 °C | 26.1 °C | 103.38 mm |
| September | 10.8 °C | 22.1 °C | 97.03 mm |
| October | 4.2 °C | 14.8 °C | 71.12 mm |
| November | -2.7 °C | 6.3 °C | 52.07 mm |
| December | -8.9 °C | -0.8 °C | 40.13 mm |
| Annual | 2.7 °C | 12.8 °C | 954.54 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°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 |