Seneca, South Dakota has a Humid Continental Hot Summers With Dry Winters climate (Köppen classification: Dwa). Average annual temperatures range from 0.4 °C (low) to 13.2 °C (high). Annual precipitation averages 524.8 Millimeters. 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 | -15 °C | -4.4 °C | 10.92 mm |
| February | -13 °C | -1.8 °C | 15.75 mm |
| March | -7 °C | 5.2 °C | 21.84 mm |
| April | -0.6 °C | 13.3 °C | 48.01 mm |
| May | 6.3 °C | 20.1 °C | 78.49 mm |
| June | 12.3 °C | 25.6 °C | 89.66 mm |
| July | 15 °C | 29.2 °C | 75.44 mm |
| August | 14 °C | 28.4 °C | 60.45 mm |
| September | 8.8 °C | 23.8 °C | 50.55 mm |
| October | 1.4 °C | 14.8 °C | 42.67 mm |
| November | -5.9 °C | 5.7 °C | 17.53 mm |
| December | -11.8 °C | -1.8 °C | 13.46 mm |
| Annual | 0.4 °C | 13.2 °C | 524.77 mm |
| 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 : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dwa - Humid Continental Hot Summers With Dry Winters |