Eureka, South Dakota has a Humid Continental Mild Summer With Dry Winters climate (Köppen classification: Dwb). Average annual temperatures range from 31.7 °F (low) to 53.5 °F (high). Annual precipitation averages 19.8 Inches. Eureka is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.9 °F | 21.1 °F | 0.39 in. |
| February | 7.1 °F | 25.9 °F | 0.52 in. |
| March | 18.1 °F | 38.4 °F | 0.8 in. |
| April | 30.4 °F | 54.4 °F | 1.58 in. |
| May | 43.0 °F | 66.7 °F | 3.09 in. |
| June | 53.8 °F | 76.3 °F | 3.39 in. |
| July | 58.8 °F | 82.5 °F | 3.19 in. |
| August | 56.5 °F | 81.4 °F | 2.22 in. |
| September | 46.9 °F | 72.5 °F | 1.85 in. |
| October | 33.6 °F | 56.5 °F | 1.7 in. |
| November | 20.0 °F | 39.9 °F | 0.56 in. |
| December | 9.2 °F | 26.5 °F | 0.49 in. |
| Annual | 31.7 °F | 53.5 °F | 19.78 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dwb - Humid Continental Mild Summer With Dry Winters |