Alamosa, Colorado has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -4.1 °C (low) to 15.3 °C (high). Annual precipitation averages 196.1 Millimeters. Alamosa 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 Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.7 °C | 1.2 °C | 10.67 mm |
| February | -13.7 °C | 4.7 °C | 6.1 mm |
| March | -8.2 °C | 10.9 °C | 13.97 mm |
| April | -4.2 °C | 15.1 °C | 15.75 mm |
| May | 1.1 °C | 20.2 °C | 17.53 mm |
| June | 5.2 °C | 25.8 °C | 11.94 mm |
| July | 8.4 °C | 27.5 °C | 31.75 mm |
| August | 7.3 °C | 26.3 °C | 28.45 mm |
| September | 3.1 °C | 23.2 °C | 25.4 mm |
| October | -3.7 °C | 17.1 °C | 16.76 mm |
| November | -10.6 °C | 9.3 °C | 10.16 mm |
| December | -16.7 °C | 2.1 °C | 7.62 mm |
| Annual | -4.1 °C | 15.3 °C | 196.1 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |