Altona, Colorado has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.1 °F (low) to 64.1 °F (high). Annual precipitation averages 19.3 Inches. Altona is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.3 °F | 45.4 °F | 0.68 in. |
| February | 21.0 °F | 46.2 °F | 0.84 in. |
| March | 28.1 °F | 54.8 °F | 1.67 in. |
| April | 33.8 °F | 60.4 °F | 2.55 in. |
| May | 42.8 °F | 69.0 °F | 3.16 in. |
| June | 51.9 °F | 81.2 °F | 2.06 in. |
| July | 58.1 °F | 87.4 °F | 1.86 in. |
| August | 56.1 °F | 85.3 °F | 1.54 in. |
| September | 48.4 °F | 77.5 °F | 1.97 in. |
| October | 37.0 °F | 64.5 °F | 1.41 in. |
| November | 27.5 °F | 53.1 °F | 0.92 in. |
| December | 20.2 °F | 44.8 °F | 0.67 in. |
| Annual | 37.1 °F | 64.1 °F | 19.33 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |