Dell, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 27.2 °F (low) to 53.7 °F (high). Annual precipitation averages 10.4 Inches. Dell is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.8 °F | 29.6 °F | 0.36 in. |
| February | 11.2 °F | 32.6 °F | 0.37 in. |
| March | 19.0 °F | 41.8 °F | 0.48 in. |
| April | 26.2 °F | 51.6 °F | 1.1 in. |
| May | 33.8 °F | 61.3 °F | 1.68 in. |
| June | 41.0 °F | 70.5 °F | 2.06 in. |
| July | 46.5 °F | 81.6 °F | 1.0 in. |
| August | 45.0 °F | 80.7 °F | 0.93 in. |
| September | 37.6 °F | 70.3 °F | 0.75 in. |
| October | 27.9 °F | 55.2 °F | 0.99 in. |
| November | 18.1 °F | 39.8 °F | 0.32 in. |
| December | 9.5 °F | 29.0 °F | 0.4 in. |
| Annual | 27.2 °F | 53.7 °F | 10.44 in. |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |