Casco, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.9 °F (low) to 53.1 °F (high). Annual precipitation averages 31.7 Inches. Casco is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.7 °F | 25.1 °F | 1.52 in. |
| February | 12.2 °F | 28.1 °F | 1.14 in. |
| March | 21.8 °F | 38.8 °F | 1.71 in. |
| April | 33.2 °F | 51.0 °F | 3.04 in. |
| May | 44.4 °F | 64.0 °F | 3.44 in. |
| June | 54.5 °F | 73.8 °F | 3.9 in. |
| July | 59.5 °F | 78.9 °F | 3.55 in. |
| August | 58.3 °F | 77.5 °F | 3.44 in. |
| September | 50.6 °F | 70.1 °F | 3.2 in. |
| October | 39.1 °F | 56.5 °F | 2.98 in. |
| November | 28.4 °F | 42.8 °F | 2.08 in. |
| December | 17.7 °F | 30.8 °F | 1.69 in. |
| Annual | 35.9 °F | 53.1 °F | 31.69 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |