Granton, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.8 °C (low) to 12.2 °C (high). Annual precipitation averages 860 Millimeters. Granton is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.9 °C | -4.8 °C | 27.94 mm |
| February | -13.4 °C | -2.1 °C | 26.16 mm |
| March | -6.9 °C | 4.7 °C | 43.18 mm |
| April | 0.3 °C | 12.6 °C | 80.26 mm |
| May | 7.1 °C | 19.6 °C | 101.85 mm |
| June | 12.7 °C | 24.7 °C | 125.22 mm |
| July | 14.7 °C | 26.9 °C | 98.81 mm |
| August | 13.6 °C | 25.8 °C | 104.65 mm |
| September | 8.9 °C | 21.6 °C | 96.52 mm |
| October | 2.4 °C | 14.1 °C | 72.64 mm |
| November | -4 °C | 5.4 °C | 46.48 mm |
| December | -10.8 °C | -1.8 °C | 36.32 mm |
| Annual | 0.8 °C | 12.2 °C | 860.03 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |