Elroy, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.8 °F (low) to 55.3 °F (high). Annual precipitation averages 36.9 Inches. Elroy 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 | 7.6 °F | 25.3 °F | 1.31 in. |
| February | 10.5 °F | 30.0 °F | 1.2 in. |
| March | 21.8 °F | 42.1 °F | 1.93 in. |
| April | 33.5 °F | 55.7 °F | 3.9 in. |
| May | 45.5 °F | 67.8 °F | 4.55 in. |
| June | 55.6 °F | 77.2 °F | 5.39 in. |
| July | 59.6 °F | 81.2 °F | 4.19 in. |
| August | 57.3 °F | 79.0 °F | 4.4 in. |
| September | 48.8 °F | 71.9 °F | 3.7 in. |
| October | 37.2 °F | 58.7 °F | 2.77 in. |
| November | 25.9 °F | 43.5 °F | 1.97 in. |
| December | 14.8 °F | 30.8 °F | 1.56 in. |
| Annual | 34.8 °F | 55.3 °F | 36.87 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 |