Alton, Utah has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.6 °F (low) to 60.9 °F (high). Annual precipitation averages 17.3 Inches. Alton is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.9 °F | 41.0 °F | 1.93 in. |
| February | 17.8 °F | 43.4 °F | 1.96 in. |
| March | 23.4 °F | 50.3 °F | 1.61 in. |
| April | 28.2 °F | 57.5 °F | 0.87 in. |
| May | 35.4 °F | 66.7 °F | 0.85 in. |
| June | 43.3 °F | 78.3 °F | 0.43 in. |
| July | 50.9 °F | 83.8 °F | 1.19 in. |
| August | 49.8 °F | 81.6 °F | 1.85 in. |
| September | 42.6 °F | 74.5 °F | 1.73 in. |
| October | 32.8 °F | 62.8 °F | 1.82 in. |
| November | 23.2 °F | 50.5 °F | 1.24 in. |
| December | 15.7 °F | 40.8 °F | 1.85 in. |
| Annual | 31.6 °F | 60.9 °F | 17.33 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |