Tomah, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.4 °F (low) to 55.4 °F (high). Annual precipitation averages 36.4 Inches. Tomah 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.0 °F | 25.2 °F | 1.2 in. |
| February | 9.9 °F | 30.1 °F | 1.13 in. |
| March | 21.2 °F | 42.0 °F | 1.87 in. |
| April | 33.2 °F | 55.9 °F | 3.73 in. |
| May | 45.4 °F | 68.2 °F | 4.53 in. |
| June | 55.2 °F | 77.5 °F | 5.34 in. |
| July | 59.2 °F | 81.5 °F | 4.29 in. |
| August | 56.7 °F | 79.3 °F | 4.41 in. |
| September | 48.4 °F | 72.0 °F | 3.75 in. |
| October | 37.0 °F | 58.6 °F | 2.79 in. |
| November | 25.5 °F | 43.4 °F | 1.88 in. |
| December | 14.4 °F | 30.5 °F | 1.52 in. |
| Annual | 34.4 °F | 55.4 °F | 36.44 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 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 |