Lewiston, Utah has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.7 °C (low) to 15.7 °C (high). Annual precipitation averages 444.5 Millimeters. 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 | -10 °C | 0.2 °C | 48.77 mm |
| February | -8 °C | 2.9 °C | 38.35 mm |
| March | -2.7 °C | 9.7 °C | 41.4 mm |
| April | 0.6 °C | 14.7 °C | 50.04 mm |
| May | 4.6 °C | 20 °C | 58.67 mm |
| June | 8.1 °C | 26.2 °C | 31.24 mm |
| July | 11.8 °C | 31.8 °C | 19.81 mm |
| August | 10.9 °C | 31.2 °C | 18.8 mm |
| September | 6.1 °C | 25.4 °C | 32.51 mm |
| October | 0.5 °C | 17.1 °C | 38.35 mm |
| November | -4.3 °C | 8.2 °C | 30.99 mm |
| December | -8.9 °C | 0.9 °C | 35.56 mm |
| Annual | 0.7 °C | 15.7 °C | 444.49 mm |
| 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 : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |