Lewiston, Utah has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.3 °F (low) to 60.2 °F (high). Annual precipitation averages 17.5 Inches. Lewiston 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 | 14.0 °F | 32.4 °F | 1.92 in. |
| February | 17.6 °F | 37.3 °F | 1.51 in. |
| March | 27.1 °F | 49.4 °F | 1.63 in. |
| April | 33.1 °F | 58.5 °F | 1.97 in. |
| May | 40.2 °F | 68.0 °F | 2.31 in. |
| June | 46.5 °F | 79.1 °F | 1.23 in. |
| July | 53.3 °F | 89.3 °F | 0.78 in. |
| August | 51.6 °F | 88.2 °F | 0.74 in. |
| September | 43.0 °F | 77.7 °F | 1.28 in. |
| October | 32.9 °F | 62.7 °F | 1.51 in. |
| November | 24.3 °F | 46.7 °F | 1.22 in. |
| December | 15.9 °F | 33.6 °F | 1.4 in. |
| Annual | 33.3 °F | 60.2 °F | 17.5 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 5b : -15°F to -10°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |