Delmont, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.1 °F (low) to 60.3 °F (high). Annual precipitation averages 25.8 Inches. Delmont is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.5 °F | 31.1 °F | 0.57 in. |
| February | 14.4 °F | 36.2 °F | 0.78 in. |
| March | 24.5 °F | 48.1 °F | 1.25 in. |
| April | 35.3 °F | 59.8 °F | 2.99 in. |
| May | 47.6 °F | 71.5 °F | 3.74 in. |
| June | 58.4 °F | 81.7 °F | 3.8 in. |
| July | 63.3 °F | 87.4 °F | 3.02 in. |
| August | 61.1 °F | 85.3 °F | 2.99 in. |
| September | 51.6 °F | 77.8 °F | 2.75 in. |
| October | 38.3 °F | 62.8 °F | 2.21 in. |
| November | 25.1 °F | 47.5 °F | 0.92 in. |
| December | 14.9 °F | 34.2 °F | 0.73 in. |
| Annual | 37.1 °F | 60.3 °F | 25.75 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |