Milliken, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 34.1 °F (low) to 63.8 °F (high). Annual precipitation averages 13.4 Inches. Milliken is located in USDA Plant Hardiness Zone 5b. 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 | 13.3 °F | 41.0 °F | 0.32 in. |
| February | 16.0 °F | 43.8 °F | 0.42 in. |
| March | 24.9 °F | 55.0 °F | 0.97 in. |
| April | 32.4 °F | 61.8 °F | 1.72 in. |
| May | 42.8 °F | 70.7 °F | 2.42 in. |
| June | 52.3 °F | 82.6 °F | 1.5 in. |
| July | 57.3 °F | 88.6 °F | 1.55 in. |
| August | 54.8 °F | 86.3 °F | 1.09 in. |
| September | 45.8 °F | 78.9 °F | 1.39 in. |
| October | 33.4 °F | 64.9 °F | 0.99 in. |
| November | 22.4 °F | 51.3 °F | 0.6 in. |
| December | 13.4 °F | 40.8 °F | 0.42 in. |
| Annual | 34.1 °F | 63.8 °F | 13.39 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 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |