Seneca, South Dakota has a Humid Continental Hot Summers With Dry Winters climate (Köppen classification: Dwa). Average annual temperatures range from 32.7 °F (low) to 55.7 °F (high). Annual precipitation averages 20.7 Inches. Seneca 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.0 °F | 24.1 °F | 0.43 in. |
| February | 8.6 °F | 28.7 °F | 0.62 in. |
| March | 19.4 °F | 41.3 °F | 0.86 in. |
| April | 30.9 °F | 56.0 °F | 1.89 in. |
| May | 43.3 °F | 68.1 °F | 3.09 in. |
| June | 54.2 °F | 78.1 °F | 3.53 in. |
| July | 59.0 °F | 84.5 °F | 2.97 in. |
| August | 57.2 °F | 83.2 °F | 2.38 in. |
| September | 47.8 °F | 74.8 °F | 1.99 in. |
| October | 34.5 °F | 58.7 °F | 1.68 in. |
| November | 21.3 °F | 42.2 °F | 0.69 in. |
| December | 10.7 °F | 28.7 °F | 0.53 in. |
| Annual | 32.7 °F | 55.7 °F | 20.66 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 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 | Dwa - Humid Continental Hot Summers With Dry Winters |