Calhan, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 32.6 °F (low) to 61.3 °F (high). Annual precipitation averages 16.8 Inches. Calhan is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.5 °F | 42.4 °F | 0.38 in. |
| February | 16.1 °F | 43.3 °F | 0.41 in. |
| March | 23.1 °F | 51.6 °F | 1.08 in. |
| April | 29.6 °F | 57.8 °F | 1.87 in. |
| May | 38.7 °F | 66.8 °F | 2.23 in. |
| June | 48.0 °F | 78.4 °F | 1.86 in. |
| July | 54.2 °F | 83.9 °F | 2.69 in. |
| August | 52.7 °F | 81.1 °F | 3.09 in. |
| September | 44.2 °F | 74.6 °F | 1.16 in. |
| October | 32.7 °F | 62.4 °F | 1.14 in. |
| November | 22.4 °F | 50.7 °F | 0.49 in. |
| December | 14.9 °F | 42.2 °F | 0.41 in. |
| Annual | 32.6 °F | 61.3 °F | 16.81 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| 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 | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |