Mattoon, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32 °F (low) to 52.4 °F (high). Annual precipitation averages 32.2 Inches. Mattoon 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 | 4.8 °F | 22.6 °F | 1.09 in. |
| February | 6.4 °F | 26.8 °F | 1.0 in. |
| March | 17.5 °F | 38.4 °F | 1.62 in. |
| April | 30.4 °F | 52.1 °F | 2.94 in. |
| May | 42.7 °F | 65.2 °F | 3.66 in. |
| June | 52.8 °F | 74.6 °F | 4.46 in. |
| July | 56.6 °F | 78.7 °F | 3.76 in. |
| August | 54.6 °F | 76.9 °F | 3.57 in. |
| September | 46.8 °F | 69.3 °F | 3.7 in. |
| October | 35.1 °F | 55.3 °F | 3.07 in. |
| November | 24.3 °F | 40.6 °F | 1.85 in. |
| December | 12.1 °F | 27.8 °F | 1.5 in. |
| Annual | 32 °F | 52.4 °F | 32.22 in. |
| 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 : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |