Flagler, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 34.8 °F (low) to 64.5 °F (high). Annual precipitation averages 15.9 Inches. Flagler 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 | 15.2 °F | 43.4 °F | 0.32 in. |
| February | 17.1 °F | 44.9 °F | 0.33 in. |
| March | 24.6 °F | 54.8 °F | 0.77 in. |
| April | 31.7 °F | 62.0 °F | 1.43 in. |
| May | 42.0 °F | 71.3 °F | 2.31 in. |
| June | 52.3 °F | 83.0 °F | 2.58 in. |
| July | 58.0 °F | 88.6 °F | 2.93 in. |
| August | 56.2 °F | 86.2 °F | 2.5 in. |
| September | 47.4 °F | 78.9 °F | 1.09 in. |
| October | 34.4 °F | 65.3 °F | 0.94 in. |
| November | 23.5 °F | 52.4 °F | 0.34 in. |
| December | 15.7 °F | 42.9 °F | 0.35 in. |
| Annual | 34.8 °F | 64.5 °F | 15.89 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 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 |