Haswell, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2 °C (low) to 19.8 °C (high). Annual precipitation averages 365.5 Millimeters. Haswell 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 | -9.9 °C | 7.6 °C | 7.11 mm |
| February | -8.3 °C | 9 °C | 7.87 mm |
| March | -3.8 °C | 14.7 °C | 20.57 mm |
| April | 0.6 °C | 18.5 °C | 31.75 mm |
| May | 6.7 °C | 24.1 °C | 50.29 mm |
| June | 12.4 °C | 30.3 °C | 46.99 mm |
| July | 15.4 °C | 33.1 °C | 67.82 mm |
| August | 14.6 °C | 31.6 °C | 66.29 mm |
| September | 9.3 °C | 27.6 °C | 22.35 mm |
| October | 1.6 °C | 20.4 °C | 24.89 mm |
| November | -5.1 °C | 13.1 °C | 11.18 mm |
| December | -9.6 °C | 7.5 °C | 8.38 mm |
| Annual | 2 °C | 19.8 °C | 365.49 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Exceptional Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |