Eureka, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.3 °C (low) to 12.9 °C (high). Annual precipitation averages 855.5 Millimeters. Eureka is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.6 °C | -3.4 °C | 38.1 mm |
| February | -11.3 °C | -1.3 °C | 33.78 mm |
| March | -5.4 °C | 5.1 °C | 50.29 mm |
| April | 1.3 °C | 12.7 °C | 86.61 mm |
| May | 8.1 °C | 19.5 °C | 103.12 mm |
| June | 13.7 °C | 25.1 °C | 120.65 mm |
| July | 16.1 °C | 27.6 °C | 95.25 mm |
| August | 14.9 °C | 26.4 °C | 87.88 mm |
| September | 10.3 °C | 22.4 °C | 78.49 mm |
| October | 3.7 °C | 14.7 °C | 69.6 mm |
| November | -2.5 °C | 6.8 °C | 48.51 mm |
| December | -8.7 °C | -0.3 °C | 43.18 mm |
| Annual | 2.3 °C | 12.9 °C | 855.46 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |