Ashton, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 32.7 °F (low) to 55.3 °F (high). Annual precipitation averages 22.3 Inches. Ashton 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 | 3.0 °F | 22.6 °F | 0.49 in. |
| February | 7.4 °F | 28.1 °F | 0.68 in. |
| March | 19.5 °F | 40.9 °F | 0.91 in. |
| April | 31.7 °F | 55.9 °F | 2.07 in. |
| May | 44.8 °F | 68.7 °F | 3.31 in. |
| June | 55.7 °F | 78.5 °F | 3.7 in. |
| July | 60.5 °F | 84.0 °F | 3.3 in. |
| August | 57.6 °F | 82.4 °F | 2.47 in. |
| September | 47.9 °F | 74.2 °F | 2.09 in. |
| October | 34.3 °F | 58.9 °F | 2.08 in. |
| November | 20.7 °F | 42.1 °F | 0.66 in. |
| December | 9.0 °F | 27.8 °F | 0.58 in. |
| Annual | 32.7 °F | 55.3 °F | 22.34 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 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |